Crystal structure of lactose permease in complex with an affinity inactivator yields unique insight into sugar recognition
Open Access
- 18 May 2011
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences of the United States of America
- Vol. 108 (23), 9361-9366
- https://doi.org/10.1073/pnas.1105687108
Abstract
Lactose permease of Escherichia coli (LacY) with a single-Cys residue in place of A122 (helix IV) transports galactopyranosides and is specifically inactivated by methanethiosulfonyl-galactopyranosides (MTS-gal), which behave as unique suicide substrates. In order to study the mechanism of inactivation more precisely, we solved the structure of single-Cys122 LacY in complex with covalently bound MTS-gal. This structure exhibits an inward-facing conformation similar to that observed previously with a slight narrowing of the cytoplasmic cavity. MTS-gal is bound covalently, forming a disulfide bond with C122 and positioned between R144 and W151. E269, a residue essential for binding, coordinates the C-4 hydroxyl of the galactopyranoside moiety. The location of the sugar is in accord with many biochemical studies.This publication has 39 references indexed in Scilit:
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