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PMID: 7644518 Published · ppublish English Comparative Study Journal Article Research Support, U.S. Gov't, P.H.S.

Features of MotA proton channel structure revealed by tryptophan-scanning mutagenesis.

Proceedings of the National Academy of Sciences of the United States of America ·Vol. 92 ·No. 17 ·1995-08-15 ·Pages 7946-50

Sharp LL, Zhou J, Blair DF

Abstract

The MotA protein of Escherichia coli is a component of the flagellar motors that functions in transmembrane proton conduction. Here, we report several features of MotA structure revealed by use of a mutagenesis-based approach. Single tryptophan residues were introduced at many positions within the four hydrophobic segments of MotA, and the effects on function were measured. Function was disrupted according to a periodic pattern that implies that the membrane-spanning segments are alpha-helices and that identifies the lipid-facing parts of each helix. The results support a hypothesis for MotA structure and mechanism in which water molecules form most of the proton-conducting pathway. The success of this approach in studying MotA suggests that it could be useful in structure-function studies of other integral membrane proteins.

MeSH Terms
Amino Acid Sequence Bacterial Proteins/biosynthesis,chemistry Cell Membrane/metabolism Cell Movement Cloning, Molecular Escherichia coli/metabolism,physiology Flagella/physiology Macromolecular Substances Models, Structural Molecular Sequence Data Mutagenesis, Site-Directed Plasmids Protein Structure, Secondary Recombinant Proteins/biosynthesis,chemistry Restriction Mapping Sequence Homology, Amino Acid Tryptophan
Chemicals
Bacterial Proteins Macromolecular Substances MotA protein, Bacteria Recombinant Proteins Tryptophan
Authors & Affiliations
3 authors, click to expand affiliations / ORCID
Sharp L L
Department of Biology, University of Utah, Salt Lake City 84112, USA.
Zhou J
Blair D F
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Article Info
Journal
Proceedings of the National Academy of Sciences of the United States of America
Abbr.
Proc Natl Acad Sci U S A
ISSN
0027-8424
DOI
10.1073/pnas.92.17.7946
Published
1995-08-15
Pages
7946-50
Language
English
Region
United States
NLM ID
7505876
PMCID
PMC41263
Subset
IM
Grants
NIGMS NIH HHS · 1-R01-GM46683 · United States
NCI NIH HHS · 5P30 CA42014 · United States
External Links
PubMed source DOI: 10.1073/pnas.92.17.7946 PMC Full Text View journal details
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