Silk Road Revealed: Mechanism of silk fibre formation in Bombyx mori

“The observation of no change in NMR and CD data with pH, but such dramatic morphological change observed in TEM suggests that only small subdomains withing FibH might be changing (such as NTD and the flexible linkers), allowing for extension of the solenoid, which seems to be contained within the…”

“The observation of no change in NMR and CD data with pH, but such dramatic morphological change observed in TEM suggests that only small subdomains withing FibH might be changing (such as NTD and the flexible linkers), allowing for extension of the solenoid, which seems to be contained within the…”

“This suggests a more stable molecular network is formed as the pH decreases, evidenced by increased elastic modulus.”

“Dilute solutions of NLSF were cast and left to dry slowly, to obtain the expected Silk-I diffraction pattern, with the films being characterised by fibre X-ray diffraction experiments (see Fibre X-ray diffraction in Materials and Methods in ESI).”

“In addition, we note that when predicting the torsion angles for reduced motifs in FibH, two possible populations for G residues are possible within generic GX motif (see Figure S16).”

“Although these fibrillar structures were slightly thicker than the expected solenoid (6 ± 1 nm against ca. 3 nm), acquiring higher resolution images proved difficult given the high sensitivity of the samples to beam damage.”

“Through our findings, we provide a convincing rationale for the historical disparities between native and RSF, as well as unparalleled understanding of the fibroin assembly process, from a liquid state to the remarkable structural material that constitutes silk fibre.”

“…like those observed before from Samia ricini ( Saturniid ) fibroin, 66 and recently in NSF. 67 Based on these observations and the apparent role NTD has on the reversible sol-gel transition, we propose that FibH can form high-order oligomers driven by head (NTD) interactions, making the core of…”

“Through our findings, we provide a convincing rationale for the historical disparities between native and RSF, as well as unparalleled understanding of the fibroin assembly process, from a liquid state to the remarkable structural material that constitutes silk fibre.”

“In most studies the silk dope is extracted from the posterior segment of the middle gland, where the pH is near neutral.”

“The structure of the N-terminal domain solved by X-ray crystallography has a saddle shape, with highly hydrophobic patches on the surfaces, on one side only covered by a small helix linked to the rest of the structure by a flexible spacer (Fig.”

“64,65 Beyond the morphological change, we observed the presence of supramolecular structures resembling bottle-brush structures like those observed before from Samia ricini ( Saturniid ) fibroin, 66 and recently in NSF. 67 Based on these observations and the apparent role NTD has on the reversible…”

“Through our findings, we provide a convincing rationale for the historical disparities between native and RSF, as well as unparalleled understanding of the fibroin assembly process, from a liquid state to the remarkable structural material that constitutes silk fibre.”

“The structure of the N-terminal domain solved by X-ray crystallography has a saddle shape, with highly hydrophobic patches on the surfaces, on one side only covered by a small helix linked to the rest of the structure by a flexible spacer (Fig.”

“15 A detailed discussion of these results is provided in SD.3.”

“Through our findings, we provide a convincing rationale for the historical disparities between native and RSF, as well as unparalleled understanding of the fibroin assembly process, from a liquid state to the remarkable structural material that constitutes silk fibre.”

“Illustration with optical textures was adapted from the literature.(14) In the first instance, fibroin at pH greater than”

“Through our findings, we provide a convincing rationale for the historical disparities between native and RSF, as well as unparalleled understanding of the fibroin assembly process, from a liquid state to the remarkable structural material that constitutes silk fibre.”

“Through our findings, we provide a convincing rationale for the historical disparities between native and RSF, as well as unparalleled understanding of the fibroin assembly process, from a liquid state to the remarkable structural material that constitutes silk fibre.”

“Briefly, the β -solenoid fold results from a supersecondary folding of strands as depicted in Figure 1.”

“Through our findings, we provide a convincing rationale for the historical disparities between native and RSF, as well as unparalleled understanding of the fibroin assembly process, from a liquid state to the remarkable structural material that constitutes silk fibre.”

“Here, we propose a trigonal unit cell containing a single curved strand, as depicted in Figure 1.”

“Here, we propose a trigonal unit cell containing a single curved strand, as depicted in Figure 1.”

“Through our findings, we provide a convincing rationale for the historical disparities between native and RSF, as well as unparalleled understanding of the fibroin assembly process, from a liquid state to the remarkable structural material that constitutes silk fibre.”

“As the silk duct diameter is reduced, a critical stress is reached, and NTD interactions are potentially disrupted, leaving a network dominated entirely by lateral solenoid interactions.”

“Dilute solutions of NLSF were cast and left to dry slowly, to obtain the expected Silk-I diffraction pattern, with the films being characterised by fibre X-ray diffraction experiments (see Fibre X-ray diffraction in Materials and Methods in ESI).”

“There are numerous Y residues on the predicted models, with the aromatic group hovering over methyl groups from A residues on contiguous strands (see Figure S13).”

“Through our findings, we provide a convincing rationale for the historical disparities between native and RSF, as well as unparalleled understanding of the fibroin assembly process, from a liquid state to the remarkable structural material that constitutes silk fibre.”

“We propose that FibH from B. mori is a multidomain protein with twelve low complexity domains with the ability to fold into β -solenoids.”

“The described transition would explain the transformation of cholesteric-isotropic-nematic observed before.”

“Through our findings, we provide a convincing rationale for the historical disparities between native and RSF, as well as unparalleled understanding of the fibroin assembly process, from a liquid state to the remarkable structural material that constitutes silk fibre.”

“Through our findings, we provide a convincing rationale for the historical disparities between native and RSF, as well as unparalleled understanding of the fibroin assembly process, from a liquid state to the remarkable structural material that constitutes silk fibre.”

“Through our findings, we provide a convincing rationale for the historical disparities between native and RSF, as well as unparalleled understanding of the fibroin assembly process, from a liquid state to the remarkable structural material that constitutes silk fibre.”

“Through our findings, we provide a convincing rationale for the historical disparities between native and RSF, as well as unparalleled understanding of the fibroin assembly process, from a liquid state to the remarkable structural material that constitutes silk fibre.”

“It was noted before that this helix could flip out of the hydrophobic space.”

“B) shows a high degree of orientation and is consistent both with previous Silk-I data, 14,36 and our newly proposed solenoid model.”

“11,40 This conformation implies that in the transformation from Silk-I to Silk-II, G residues would not need to go through sterically hindered angles (see Figure S17), 41 thus reducing the overall energetic cost of the Silk-I to Silk-II transformation.”

“Through our findings, we provide a convincing rationale for the historical disparities between native and RSF, as well as unparalleled understanding of the fibroin assembly process, from a liquid state to the remarkable structural material that constitutes silk fibre.”

“Through our findings, we provide a convincing rationale for the historical disparities between native and RSF, as well as unparalleled understanding of the fibroin assembly process, from a liquid state to the remarkable structural material that constitutes silk fibre.”

“It was noted before that this helix could flip out of the hydrophobic space.”

“Through our findings, we provide a convincing rationale for the historical disparities between native and RSF, as well as unparalleled understanding of the fibroin assembly process, from a liquid state to the remarkable structural material that constitutes silk fibre.”

“…Samia ricini ( Saturniid ) fibroin, 66 and recently in NSF. 67 Based on these observations and the apparent role NTD has on the reversible sol-gel transition, we propose that FibH can form high-order oligomers driven by head (NTD) interactions, making the core of the supramolecular fibre (SD.11).”

“29 However, the second population of torsion angles (ca. ϕ, φ = -80°, 180°) was not used to constrain the modelling and matches closely those found in the solenoidal model predicted by ColabFold as well as previously proposed angles from density functional theory (DFT) calculations.”

“Here we observed that the protein appeared as globules with an apparent size of about 24 ±8 nm at pH 8, but elongated fibrillar structures were observed at pH 6 (SD.10).”

“B) shows a high degree of orientation and is consistent both with previous Silk-I data, 14,36 and our newly proposed solenoid model.”

“The NTD and CTD are involved in the folding, assembly, and secretion of silk proteins, and extremely conserved across silkworm strains [9–14].”

“To some extent, these experiments verify previous observations 10 , wheresilkproteinsdisplayedsmallerhydrodynamicdiameters,hence,faster diffusionratesathigherpH.”