Monoclonal antibody 4B1 influences the p K a of Glu325 in lactose permease (LacY) from Escherichia coli : evidence from SEIRAS

The monoclonal antibody 4B1 binds to a conformational epitope on the periplasmic side of lactose permease (LacY) of Escherichia coli and inhibits H + /lactose symport and lactose efflux under nonenergized conditions. At the same time, ligand binding and translocation reactions that do not involve ne...

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Bibliographic Details
Published inFEBS letters Vol. 594; no. 20; pp. 3356 - 3362
Main Authors Omeis, Fatima, Santos Seica, Ana Filipa, Ermolova, Natalia, Kaback, H. Ronald, Hellwig, Petra
Format Journal Article
LanguageEnglish
Published Wiley 26.10.2020
Subjects
Chemical Sciences
Other
surface-enhanced infrared absorption spectroscopy
monoclonal antibody 4B1
membrane protein
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Summary:The monoclonal antibody 4B1 binds to a conformational epitope on the periplasmic side of lactose permease (LacY) of Escherichia coli and inhibits H + /lactose symport and lactose efflux under nonenergized conditions. At the same time, ligand binding and translocation reactions that do not involve net H + translocation remain unaffected by 4B1. In this study, surface‐enhanced infrared absorption spectroscopy applied to the immobilized LacY was used to study the pH‐dependent changes in LacY and to access in situ the effect of the 4B1 antibody on the p K a of Glu325, the primary functional H + ‐binding site in LacY. A small shift of the p K value from 10.5 to 9.5 was identified that can be corroborated with the inactivation of LacY upon 4B1 binding.
ISSN:0014-5793
1873-3468
DOI:10.1002/1873-3468.13907