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Glu-537, not Glu-461, is the nucleophile in the active site of (lac Z) beta-galactosidase from Escherichia coli.
Open accessAbstract
The covalent intermediate formed during catalysis by the lac Z beta-galactosidase from Escherichia coli can be trapped by reaction of the enzyme with 2',4'-dinitrophenyl 2-deoxy-2-fluoro-beta-D-galactopyranoside, thereby inactivating the enzyme. Kinetic parameters for this inactivation process with the holo- and apo-enzymes have been determined. The intermediate so formed turns over only very slowly (t1/2 = 11.5 h) resulting in reactivation of the enzyme. The nucleophilic amino acid involved has been identified as Glu-537 by using a tritium-labeled inactivator to label the enzyme, then cleaving the labeled protein into peptides and purifying and sequencing the labeled peptide. This residue is conserved in five homologous beta-galactosidases and is different from that (Glu-461) proposed to be the nucleophile (Herrchen, M., and Legler, G. (1984) Eur. J. Biochem. 138, 527-531) on the basis of affinity labeling studies with conduritol C cis-epoxide. A role for glutamic acid residue 461 as the acid/base catalyst is proposed and justified.
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Citations
Cited by
New families in the classification of glycosyl hydrolases based on amino acid sequence similarities
Henrissat, B., & Bairoch, A. (1993) · Biochemical Journal · doi:10.1042/bj2930781 · Cited by 1,974
Three-dimensional structure of β-galactosidase from E. coli.
Jacobson, R. H., Zhang, X.-J., DuBose, R. F., & Matthews, B. W. (1994) · Nature · doi:10.1038/369761a0 · Cited by 600
Directed evolution of a fucosidase from a galactosidase by DNA shuffling and screening
Zhang, J.-H., Dawes, G., & Stemmer, W. P. C. (1997) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.94.9.4504 · Cited by 270
A Covalent Enzyme-Substrate Intermediate with Saccharide Distortion in a Mutant T4 Lysozyme
Kuroki, R., Weaver, L. H., & Matthews, B. W. (1993) · Science · doi:10.1126/science.8266098 · Cited by 193
Fonzi, W. A. (1999) · Journal of Bacteriology · doi:10.1128/jb.181.22.7070-7079.1999 · Cited by 193
Metadata
- Authors
- Gebler, J. C., Aebersold, R., & Withers, S. G.
- Venue
- Journal of Biological Chemistry
- Publisher
- Elsevier BV
- Published
- 1992-06
- Volume
- 267
- Issue
- 16
- Pages
- 11126-11130
- ISSN
- 0021-9258 (ISSN-L)
- OpenAlex
- W1605271364
- Cited by
- 171
- References
- 0
- FWCI
- 12.41
- Type
- journal article
- Language
- en
- Open access
- hybrid
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- CoChat. (2026). Citation check: Glu-537, not Glu-461, is the nucleophile in the active site of (lac Z) beta-galactosidase from Escherichia coli. https://app.cochat.ai/papers/10.1016/s0021-9258(19)49884-0
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- Gebler, J. C., Aebersold, R., & Withers, S. G. (1992). Glu-537, not Glu-461, is the nucleophile in the active site of (lac Z) beta-galactosidase from Escherichia coli. Journal of Biological Chemistry. https://doi.org/10.1016/s0021-9258(19)49884-0
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Contains information from the Semantic Scholar Academic Graph Datasets, made available under the ODC Attribution License (ODC-BY 1.0).
Semantic Scholar’s data is described in: Kinney, R., et al. (2023). The Semantic Scholar Open Data Platform. arXiv:2301.10140.
