Cited by 330Topological and Geometric Data AnalysisComputational Drug Discovery MethodsMachine Learning in Bioinformatics

TopologyNet: Topology based deep convolutional and multi-task neural networks for biomolecular property predictions

Open access
Cang, Zixuan, Wei, Guo-Wei·2017·PLOS Computational Biology

Abstract

Although deep learning approaches have had tremendous success in image, video and audio processing, computer vision, and speech recognition, their applications to three-dimensional (3D) biomolecular structural data sets have been hindered by the geometric and biological complexity. To address this problem we introduce the element-specific persistent homology (ESPH) method. ESPH represents 3D complex geometry by one-dimensional (1D) topological invariants and retains important biological information via a multichannel image-like representation. This representation reveals hidden structure-function relationships in biomolecules. We further integrate ESPH and deep convolutional neural networks to construct a multichannel topological neural network (TopologyNet) for the predictions of protein-ligand binding affinities and protein stability changes upon mutation. To overcome the deep learning limitations from small and noisy training sets, we propose a multi-task multichannel topological convolutional neural network (MM-TCNN). We demonstrate that TopologyNet outperforms the latest methods in the prediction of protein-ligand binding affinities, mutation induced globular protein folding free energy changes, and mutation induced membrane protein folding free energy changes. AVAILABILITY: weilab.math.msu.edu/TDL/.

AI snapshot

Written from the paper’s full text.

TL;DR

TopologyNet introduces element-specific persistent homology (ESPH) to represent 3D biomolecular structures as multichannel 1D topological images and integrates this representation with deep convolutional and multi-task neural networks. It reports improved predictions for protein-ligand binding affinity and mutation-induced protein stability changes over prior methods.

Key findings

  • For protein-ligand binding affinity on PDBBind 2007, TNet-BP achieved median RP = 0.826 and RMSE = 1.37, with best RP = 0.828 and best RMSE = 1.37; on PDBBind v2016, median RP = 0.81 and RMSE = 1.34.
  • For mutation-induced globular protein stability changes, TNet-MP-2 achieved RP = 0.81 and RMSE = 0.94 on S350, and RP = 0.77 and RMSE = 0.94 on S2648 5-fold cross validation; TNet-MP-1 using only topological information achieved RP = 0.74/RMSE = 1.07 on S350 and RP = 0.72/RMSE = 1.02 on S2648.
  • For membrane protein mutation impacts, multi-task TNet-MMP-2 improved RP from 0.52 to 0.57, a 9.6% improvement over TNet-MMP-1, with RMSE = 1.09 versus 1.15; the paper reports these as the best among tested methods.
  • Feature ablation showed dimension 0 features gave RP (RMSE) of 0.73 (1.09) for mutation and 0.82 (1.40) for binding, dimensions 1 and 2 gave 0.66 (1.21) and 0.78 (1.54), and combining all dimensions gave 0.74 (1.08) and 0.83 (1.37), respectively.

Methods

  • ESPH converts 3D biomolecular structures into element-specific topological fingerprints using persistent homology barcodes, then encodes birth, death, and persistence patterns into structured 1D image-like multichannel vectors.
  • TopologyNet uses multichannel topological convolutional neural networks with locally connected layers, dropout, bagging, and SGD with momentum; MM-TCNN shares convolution layers and branches into task-specific fully connected layers for multi-task learning.
  • Data included PDBBind 2007 core set (195 test complexes) with refined set minus core (1105 training complexes), PDBBind v2016 refined set (4057 complexes; 3767 training, 290 test), S2648 (2648 mutation instances in 131 proteins), S350 subset, and M223 (223 membrane protein mutation instances across 7 families) with 5-fold cross validation.

Limitations

  • The paper states membrane protein mutation data are relatively small, between 200 and 300 proteins, and noisy/less reliable; it also states TNet membrane results are “not satisfactory” though best among tested methods.
  • The paper states there is no obvious transferable property of convolution filters along the distance scale, motivating locally connected layers, and suggests higher-dimensional Betti numbers in more abstract complexes may enrich the representation.
  • Evident from the text: mutation modeling analyzes only folded states and not unfolded states due to sampling cost; hydrogens are typically absent from PDB structures and are not used; the reported membrane protein performance remains modest.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1371/journal.pcbi.1005690

Cites

147 of 147 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 11 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    TNet-BP outperforms all the other scoring functions reported by Li et al [59] on the task of binding affinity prediction from structures.

    “TNet-BP outperforms all the other scoring functions reported by Li et al [59] on the task of binding affinity prediction from structures.”
    • Also stated in: § Abstract · boosted
      “We demonstrate that TopologyNet outperforms the latest methods in the prediction of protein-ligand binding affinities”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [59] H Li, 2015, Improving AutoDock Vina using random forest: the growing accuracy of binding affinity prediction by the effective exploitation of larger data sets, Molecular Informatics source

      Not checked in the free run.

  • Findingreasoning

    TNet-MP-2 significantly improves over TNet-MP-1 on mutation prediction.

    “TNet-MP-2 is able to significantly improve our original topological prediction”
    Quote in the paperSubstantial claim
  • Findingown data

    The multi-task algorithm improves the Pearson correlation coefficient of membrane protein mutation prediction by 9.6%, from 0.52 to 0.57.

    “Pearson correlation coefficient of membrane protein mutation prediction is improved by 9.6%, i.e., from 0.52 to 0.57 by the multi-task algorithm that trains and predicts the present “M223” data set with the “S2648” date set.”
    Quote in the paperSubstantial claim
  • Findingown data

    TNet results are the best among the methods tested on membrane protein mutation prediction.

    “Our TNet results, though not satisfactory, are the best among the methods tested on this problem.”
    • Also stated in: § Abstract · boosted
      “We demonstrate that TopologyNet outperforms the latest methods in the prediction of protein-ligand binding affinities, mutation induced globular protein folding free energy changes, and mutation induced membrane protein folding free energy changes.”
    Quote in the paperSubstantial claim
  • Findingown data

    Combination of all dimension features results in RP (RMSE) of 0.74 (1.08) for mutation prediction.

    “The combination of all dimension features results in better RP (RMSE) of 0.74 (1.08) and 0.83 (1.37), respectively for the mutation and binding predictions, showing that two sets of features both contribute to predictions.”
    Quote in the paperSubstantial claim
  • May combine two claims. 21
  • The quote only partly states this claim. 1
  • Classified as probably not a substantial claim. 30
  • May combine two claims.

    Findingown data

    TNet-MMP-2 achieved RP 0.57 and RMSE 1.09 on the M223 data set.

    “| TNet-MMP-2d | 0.57 | 1.09 |”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    On the S2648 set, TNet-MP-2 achieved RP 0.77 and RMSE 0.94.

    “| TNet-MP-2 | 350 | 0.81 | 0.94 | 2648 | 0.77 | 0.94 |”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    On the PDBBind v2016 refined set, TNet-BP achieved median RP 0.81 and RMSE 1.34 pKd/pKi units.

    “The median RP and RMSE are 0.81 and 1.34 pKd/pKi units, respectively.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    On the PDBBind 2007 core set, TNet-BP achieved a median Pearson correlation coefficient of 0.826 and RMSE of 1.37 pKd/pKi units.

    “| TNet-BP | 0.826a | 1.37 |”
    • Also stated in: § Deep learning prediction of protein-ligand binding affinities · plain
      “a Median results (The best RP = 0.828 and best RMSE = 1.37 for this method).”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    On the S350 set, TNet-MP-2 achieved RP 0.81 and RMSE 0.94.

    “| TNet-MP-2 | 350 | 0.81 | 0.94 | 2648 | 0.77 | 0.94 |”
    Quote in the paperSubstantial claim
  • The quote only partly states this claim.

    Findingown data

    TNet-MP-2 outperforms other methods on the S350 and S2648 mutation prediction tasks.

    “We demonstrate that TopologyNet outperforms the latest methods in the prediction of protein-ligand binding affinities, mutation induced globular protein folding free energy changes, and mutation induced membrane protein folding free energy changes.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingcitation

    For protein-ligand binding v2007, the handcrafted features and gradient boosting trees method has RP (RMSE) 0.82 (1.40), the TopologyNet method has 0.83 (1.37), and averaging them achieves 0.84 (1.35).

    “Our method based on handcrafted features and gradient boosting trees with performance 0.82 (1.40) [61] and the method presented in this work with performance 0.83 (1.37) can achieve improved performance of 0.84 (1.35) when the two results are combined by averaging.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [61] Z Cang, 2017, Integration of element specific persistent homology and machine learning for protein-ligand binding affinity prediction, International Journal for Numerical Methods in Biomedical Engineering

      Not checked in the free run.

  • May combine two claims.

    Findingown data

    Averaging the results of the two methods for S350 improves performance to 0.83 (0.89), better than both individual methods.

    “When the results are averaged for the two methods, the performance is improved to 0.83 (0.89) which is better than both individual methods.”
    Quote in the paperSubstantial claim
  • May combine two claims.

    Findingown data

    The slope of linear fitting of predicted values to experimental data is 0.66 for the neural network based method and 0.60 for the GBT based method.

    “The slope of linear fitting of the predicted values to the experimental data is 0.66 for the neural network based method and 0.60 for the GBT based method which also illustrates that the neural network based method handles border cases better.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Premisenone given

    Dimension 1 and dimension 2 topological features characterize the hydrophobic network and geometric rings and voids.

    “In contrast, dimension 1 and dimension 2 topological features characterize the hydrophobic network and geometric rings and voids.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Premisereasoning

    Mutation data for the large globular protein data set are more reliable, while those for the small membrane protein data set are noisy and less reliable because current membrane protein mutagenesis technologies are immature.

    “The mutation data of the large data set for globular proteins are more reliable, while those of the small data set for membrane proteins are noisy and less reliable due to the fact that the current technologies for membrane protein mutagenesis experiments are immature.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: Current technologies for membrane protein mutagenesis experiments are immature.
  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationreasoning

    Neural networks have relatively high underlying randomness from random weight initialization and random mini-batch partition, so they can benefit from bagging even when individual models are trained on the same dataset.

    “Specifically, as neural networks have relatively high underlying randomness caused by factors including the random weights initialization and the random mini-batch partition, it can benefit from bagging even if the individual models are trained on the same dataset.”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: Models with randomness in the training process likely make different errors on testing data.
  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    There are strong, moderate and weak hydrogen bond interactions with donor-acceptor distances of 2.2-2.5Å, 2.5-3.2Å, and 3.2-4.0Å, respectively.

    “Moreover, Jeffrey suggested that there are strong, moderate and weak hydrogen bond interactions with donor-acceptor distances of 2.2-2.5Å, 2.5-3.2Å, and 3.2-4.0Å, respectively [99].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [99] GA Jeffrey, 1997, An introduction to hydrogen bonding

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductown data

    The proposed method was evaluated using 5-fold cross validation on the S2648 and M223 datasets.

    “The proposed method is tested on a data set of 2648 mutation instances of 131 proteins named “S2648” data set [86] in a 5-fold cross validation task over the “S2648” set”
    • Also stated in: § Multi-task deep learning prediction of membrane protein mutation impacts · plain
      “The proposed method is tested on a set of 223 mutation instances of membrane proteins covering 7 protein families named “M223” data set [98] with 5-fold cross validation.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [86] Y Dehouck, 2009, Fast and accurate predictions of protein stability changes upon mutations using statistical potentials and neural networks: PoPMuSiC-2.0, Bioinformatics source

      Not checked in the free run.

    • cites [98] BM Kroncke, 2016, Documentation of an Imperative To Improve Methods for Predicting Membrane Protein Stability, Biochemistry source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationreasoning

    The task of globular protein mutation predictions helps extract higher level features from low level topological representations.

    “Intuitively, the task of globular protein mutation predictions help to extract higher level features from low level topological representations.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The popular multi-task learning framework built on linear regression with regularization techniques lacks the ability to extract the relationship between very low level descriptors and the target quantity.
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    0-dimensional TFs describe intramolecular interactions between the protein and ligand.

    “Here, 0-dimensional TFs describe intramolecular interactions between the protein and ligand.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationown data

    Two sets of features, dimension 0 and dimensions 1 and 2, both contribute to predictions.

    “The combination of all dimension features results in better RP (RMSE) of 0.74 (1.08) and 0.83 (1.37), respectively for the mutation and binding predictions, showing that two sets of features both contribute to predictions.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing), S4 (based).

    Interpretationnone given

    The flexible and hierarchical structure of neural network allows seamless combination of automatically extracted features and handcrafted features.

    “The flexible and hierarchical structure of neural network allows seamless combination of automatically extracted features and handcrafted features.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Premisereasoning

    Properties that reside in different distance scales are heterogeneous, so unlike images or videos, there is no obvious transferable property of convolution filters along the convolution dimension in the proposed method.

    “Properties that reside in different distance scales are heterogeneous so unlike images or videos, there is no obvious transferable property of the convolution filters along the convolution dimension in the proposed method.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Traditional machine learning approaches require manual extraction of features for each domain of application.

    “Traditional machine learning approaches require manual extraction of features for each domain of application.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The dropout technique is an easy way of preventing network overfitting.

    “The dropout technique is an easy way of preventing network overfitting [100].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [100] N Srivastava, 2014, Dropout: a simple way to prevent neural networks from overfitting, Journal of Machine Learning Research

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    All heavy atom TFs delineate the geometric effect of protein-ligand binding.

    “All heavy atom TFs delineate the geometric effect of protein-ligand binding.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Premisenone given

    ESTFs between nitrogen and oxygen atoms correlate to hydrophilic interactions and/or hydrogen bonds in biomolecules.

    “Similarly ESTFs between nitrogen and oxygen atoms correlate to hydrophilic interactions and/or hydrogen bonds in biomolcules.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    Convolutional neural network facilitates automatic feature extraction from multichannel topological invariant inputs.

    “Convolutional neural network facilitates the automatic feature extraction from multichannel topological invariant inputs.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Interpretationnone given

    Element-specific persistent homology reduces geometric and biological complexities and provides a sufficient and structured low level representation for neural networks.

    “In this framework, element-specific persistent homology reduces geometric and biological complexities and provides a sufficient and structured low level representation for neural networks.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    The all heavy atom topological representation of proteins does not provide enough biological information about protein structures, such as bond length distribution of a given type of atoms, hydrogen bonds, hydrophobic and hydrophilic effects.

    “The all heavy atom topological representation of proteins does not provide enough biological information about protein structures, such as bond length distribution of a given type of atoms, hydrogen bonds, hydrophobic and hydrophilic effects, etc.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Knowledge based scoring functions outperform other scoring functions.

    “Given the current massive and complex data challenges, knowledge based scoring functions outperform other scoring functions. [65].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [65] Z Zheng, 2011, Ligand Identification Scoring Algorithm (LISA), Journal of Chemical Information and Model source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Interpretationnone given

    When the convolutional neural network is applied, convolution layers identify local patterns of atomic interactions and fully connected layers extract higher level descriptions by combining local patterns at various distance scales.

    “When the convolutional neural network is applied, the convolution layers identify local patterns of atomic interactions and the fully connected layers then extract higher level descriptions of the system by combining local patterns at various distance scales.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    It is important to keep track of the birth, death, and persistence patterns of the barcodes because this information is associated with the bond length, ring or cavity size, flexibility and steric effect.

    “Additionally, as shown in Fig 2, it is important to keep track of the birth, death, and persistence patterns of the barcodes, because this information is associated with the bond length, ring or cavity size, flexibility and steric effect.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    Tasks with insufficient training data sets are more likely to benefit from information collected from tasks with large training sets in a multi-task learning framework.

    “Finally, tasks with insufficient training data sets will be more likely to benefit from the information collected from tasks with large training sets in a multi-task learning framework.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based).

    Study design and conductnone given

    It is not valid to do bagging of predictors on different cross validation splits.

    “Bagging of only 20 models is performed here because it is not valid to do bagging of predictors on different cross validation splits.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Vr reflects the 0th order topological connectivity information.

    “Generally speaking, Vr also reflects the 0th order topological connectivity information.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based). May combine two claims.

    Premisenone given

    Unfolded states of proteins are highly dynamic, which significantly increases modeling cost due to the need of sampling over large conformation space.

    “Since unfolded states of proteins are highly dynamic which significantly increases the modeling cost due to the need of sampling over large conformation space, we only analyze the folded states of the mutants and the wild type proteins in this application.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Vr is not equivalent to Vd in most simplicial complex setups.

    “It should be noted that Vr is not equivalent to Vd in most simplicial complex setups.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationreasoning

    The flexible and hierarchical structure of neural network makes it easy to implement multi-task learning by combining related tasks to a desired level of model sharing by tuning the layer of model branching.

    “It also makes it easy to implement multi-task learning by combining related tasks to a desired level of model sharing by tuning the layer of model branching.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given

    Betti-1 and Betti-2 ESTFs from carbon atoms are associated with hydrophobic interaction networks in biomolecules.

    “For example, Betti-1 and Betti-2 ESTFs from carbon atoms are associated with hydrophobic interaction networks in biomolecules.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationnone given

    Common topological attributes and underlying physical interactions in features provide a basis for multi-task predictions.

    “The common topological attributes and underlying physical interactions in features provide a basis for multi-task predictions.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Neural networks with several convolution layers and fully connected layers possess a large number of degrees of freedom which can easily lead to overfitting.

    “Neural networks with several convolution layers and fully connected layers possess a large number of degrees of freedom which can easily lead to overfitting.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationreasoning

    Methods of ensembles of trees and neural network based methods may result in different error characteristics for different samples and can potentially improve predictive power by correcting each other's error when averaged.

    “Therefore, similar to the idea of bagging, methods of ensembles of trees and neural network based methods may result in different error characteristics for different samples and can potentially improve the predictive power by correcting each others’ error when the results from different models are averaged.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: In many applications, where among the dataset there are just a handful of samples with large absolute value for the target property, methods of ensembles of trees tend to overestimate (underestimate) the border cases with very negative (positive) target values.
    • Rests on an assumption: Data samples are generally unevenly distributed.
  • May combine two claims.

    Interpretationown data

    The proposed TopologyNet methods have been shown to outperform other existing methods in protein-ligand binding affinity predictions and mutation induced protein stability change predictions.

    “The proposed topology based neural network (TopologyNet) methods have been shown to outperform other existing methods in protein-ligand binding affinity predictions and mutation induced protein stability change predictions.”
    Quote in the paperSubstantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Premisenone given

    TFs of carbon atoms account for hydrophobic effects and also implicitly reflect the solvation effects.

    “The TFs of carbon atoms account for hydrophobic effects and also implicitly reflect the solvation effects.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Dimension 0 inputs describe pairwise atomic interactions.

    “Intuitively, the dimension 0 inputs describe pairwise atomic interactions, which clearly contribute to the prediction of the target properties.”
    Quote in the paperNot a substantial claim
  • May combine two claims.

    Interpretationreasoning

    Convolutional neural networks can learn from data to extract high level representations of biomolecular systems while retaining spatial relationships, and construct mappings from these representations to target properties.

    “Given this representation, convolutional neural networks can then learn from data to extract high level representations of the biomolecular systems, while retaining the spatial relationships, and construct mappings from these representations to the target properties.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given

    One advantage of multichannel topological convolutional deep neural networks is their ability to extract features hierarchically from low level topological representations.

    “One of the advantages of multichannel topological convolutional deep neural networks is their ability to extract features hierarchically from low level topological representations.”
    Quote in the paperNot a substantial claim
44 of 44
  • The paper relies on this without support.

    Ordinary persistent homology oversimplifies biological information.

    “However, ordinary persistent homology oversimplifies biological information.”
  • The paper relies on this without support.

    The popular multi-task learning framework built on linear regression with regularization techniques lacks the ability to extract the relationship between very low level descriptors and the target quantity.

    “While the popular multi-task learning framework built on linear regression with regularization techniques lacks the ability to extract the relationship between very low level descriptors and the target quantity.”
  • The paper relies on this without support.

    The small size of membrane protein mutation data limits the success of data driven approaches, such as ensemble of trees.

    “The small size of membrane protein mutation data limits the success of data driven approaches, such as ensemble of trees.”
  • The authors state this as an assumption.

    1D biomolecular persistent barcodes are able to effectively characterize 3D biomolecular structures.

    “A basic assumption of persistent homology as applied to biomolecular function prediction is that 1D biomolecular persistent barcodes are able to effectively characterize 3D biomolecular structures.”
  • The paper relies on this without support.

    In many applications, where among the dataset there are just a handful of samples with large absolute value for the target property, methods of ensembles of trees tend to overestimate (underestimate) the border cases with very negative (positive) target values.

    “It has been observed that in many applications, where among the dataset, there are just a handful of samples with large absolute value for the target property, methods of ensembles of trees tend to overestimate (underestimate) the border cases with very negative (positive) target values.”
  • The paper relies on this without support.

    Data samples are generally unevenly distributed.

    “Additionally, it is generally the case that data samples are unevenly distributed.”
  • The authors state this as an assumption.

    Models with randomness in the training process likely make different errors on testing data.

    “This is based on the assumption that models with randomness in the training process likely make different errors on testing data.”
  • The paper relies on this without support.

    Current technologies for membrane protein mutagenesis experiments are immature.

    “due to the fact that the current technologies for membrane protein mutagenesis experiments are immature”
8 of 8

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • The integration of ESPH and machine learning gives rise to some of the most accurate predictions of protein-ligand binding affinities and mutation induced protein stability changes.

    “The integration of ESPH and machine learning gives rise to some of the most accurate predictions of protein-ligand binding affinities 27,28 and mutation induced protein stability changes. 26,28”
  • Element specific persistent homology barcodes can be transformed to image-like representations and used in 1-dimensional or 2-dimensional convolutional neural networks.

    “The barcodes can also be transformed to representations similar to images and used in a 1-dimensional or a 2-dimensional convolutional neural networks [22, 23].”
  • Topological descriptors integrated with deep learning achieved state-of-the-art prediction of binding affinity.

    “Topological descriptors were further integrated with a variety of deep learning algorithms to achieve state-of-the-art analysis and prediction of protein folding stability change upon mutation [38], drug toxicity [39], aqueous solubility [40], partition coefficient [40], binding affinity [21, 22], and the virtual screening of active ligands and decoys [23].”
  • Applying convolutional neural networks and multi-task learning in the paper's predictions further advanced the capability of the models.

    “We applied convolutional neural networks and multi-task learning in our predictions which further advanced the capability of our models [22, 23].”
  • Fixed-length features derived from element specific persistent homology barcodes can be used with ensemble of trees and deep learning neural networks.

    “These fixed length features can be used with powerful machine learning methods such as the ensemble of trees and deep learning neural networks [21, 22].”

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Table 3 footnote names the wrong membrane-protein data set

    Minor

    The paper names the membrane-protein mutation data set "M223," but the footnote says TNet-MMP-1 uses features from an "S223" data set.

1 of 1

Cites

Flagged first, then by citations

Research works printed but not linked: 4

  1. X Shi, 2011, Geometry and topology for modeling biomolecular surfaces, Far East J Applied Math, 50, 1
  2. T Kaczynski, 2004, vol. 157 of Applied Mathematical Sciences
  3. Robins V. Towards computing homology from finite approximations. In: Topology Proceedings. vol. 24; 1999. p. 503–532.
  4. Theano Development Team. Theano: A Python framework for fast computation of mathematical expressions. arXiv e-prints. 2016;abs/1605.02688.

Cited by

Sorted by citations

Authors
Cang, Z., & Wei, G.-W.
Affiliations
Michigan State University (US)
Corresponding author
Wei, Guo-Wei
Venue
PLOS Computational Biology
Published
2017-07-27
Volume
13
Issue
7
Pages
e1005690
ISSN
  • 1553-734X (ISSN-L)
  • 1553-7358
OpenAlex
W2741292700
Cited by
330
References
147
Citations by year
2026: 30 · 2025: 53 · 2024: 41 · 2023: 44 · 2022: 35 · 2021: 39 · 2020: 39 · 2019: 27 · 2018: 19 · 2017: 3
FWCI
18.06
Type
journal article
Language
en
Open access
Locations
  • PLoS Computational Biology (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • arXiv (Cornell University) (submittedVersion)
  • RePEc: Research Papers in Economics (submittedVersion)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
  • Figshare (submittedVersion, cc-by)
  • arXiv (Cornell University)
Funders
National Science Foundation (IIS-1302285, DMS-1721024)
Topics
  • Physical Sciences › Computer Science › Computational Theory and Mathematics › Topological and Geometric Data Analysis
  • Physical Sciences › Computer Science › Computational Theory and Mathematics › Computational Drug Discovery Methods
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Machine Learning in Bioinformatics
Keywords
topological invariants, protein-ligand binding affinity prediction, protein stability prediction, mutation effects, folding free energy, membrane protein folding, multi-channel convolutional neural network, multi-task learning, structure-function relationship
MeSH terms
Machine Learning, Image Processing, Computer-Assisted, Membrane Proteins, Protein Binding, Models, Statistical, Neural Networks, Computer, Protein Folding, Computational Biology, Molecular Dynamics Simulation

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-10.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-10.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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