ArticleProceedings of the National Academy of Sciences of the United States of America2014
Real-time conformational changes in LacY.
Article in Proceedings of the National Academy of Sciences of the United States of America, 2014. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 18 papers.
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Who cites it
18 citing papers in PubMed, 27 citations in OpenAlex.
- Article
- CH•••S hydrogen bonds drive molecular recognition of ergothioneine by the microbial transporter.Science advances · 2026Article
- Transport mechanism of DgoT, a bacterial homolog of SLC17 organic anion transporters.The EMBO journal · 2024Article
- Mechanistic aspects of IPTG (isopropylthio-β-galactoside) transport across the cytoplasmic membrane of Escherichia coli-a rate limiting step in the induction of recombinant protein expression.Journal of industrial microbiology & biotechnology · 2023Article
- Discovery and structure of a widespread bacterial ABC transporter specific for ergothioneine.Nature communications · 2022Article
- Article
- Function Trumps Form in Two Sugar Symporters,International journal of molecular sciences · 2021Review
- Article
- Engineered occluded apo-intermediate of LacY.Proceedings of the National Academy of Sciences of the United States of America · 2018Article
- Crystal Structure of a ligand-bound LacY-Nanobody Complex.Proceedings of the National Academy of Sciences of the United States of America · 2018Article
- Oversized galactosides as a probe for conformational dynamics in LacY.Proceedings of the National Academy of Sciences of the United States of America · 2018Article
- An Asymmetric Conformational Change in LacY.Biochemistry · 2017Article
- Article
- Crystal structure of a LacY-nanobody complex in a periplasmic-open conformation.Proceedings of the National Academy of Sciences of the United States of America · 2016Article
- A Numbering System for MFS Transporter Proteins.Frontiers in molecular biosciences · 2016Article
- Transient conformers of LacY are trapped by nanobodies.Proceedings of the National Academy of Sciences of the United States of America · 2015Article
- Outward-facing conformers of LacY stabilized by nanobodies.Proceedings of the National Academy of Sciences of the United States of America · 2014Article
- Article
Corrections and comments
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Authors and funding
3 authors at 1 institution in 2 countries.
Funding
Abstract
Galactoside/H(+) symport across the cytoplasmic membrane of Escherichia coli is catalyzed by lactose permease (LacY), which uses an alternating access mechanism with opening and closing of deep cavities on the periplasmic and cytoplasmic sides. In this study, conformational changes in LacY initiated by galactoside binding were monitored in real time by Trp quenching/unquenching of bimane, a small fluorophore covalently attached to the protein. Rates of change in bimane fluorescence on either side of LacY were measured by stopped flow with LacY in detergent or in proteoliposomes and were compared with rates of galactoside binding. With LacY in proteoliposomes, the periplasmic cavity is tightly sealed and the substrate-binding rate is limited by the rate of opening of this cavity. Rates of opening, measured as unquenching of bimane fluorescence, are 20-30 s(-1), independent of sugar concentration and essentially the same in detergent or in proteoliposomes. On the cytoplasmic side of LacY in proteoliposomes, slow bimane quenching (i.e., closing of the cavity) is observed at a rate that is also independent of sugar concentration and similar to the rate of sugar binding from the periplasmic side. Therefore, opening of the periplasmic cavity not only limits access of sugar to the binding site of LacY but also controls the rate of closing of the cytoplasmic cavity.
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