Structure-function of cyanobacterial outer-membrane protein, Slr1270: homolog of Escherichia coli drug export/colicin import protein, TolC.

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TitleStructure-function of cyanobacterial outer-membrane protein, Slr1270: homolog of Escherichia coli drug export/colicin import protein, TolC.
Publication TypeJournal Article
Year of Publication2014
AuthorsAgarwal, R, Zakharov, S, S Hasan, S, Ryan, CM, Whitelegge, JP, Cramer, WA
JournalFEBS Lett
Volume588
Issue21
Pagination3793-801
Date Published2014 Nov 03
ISSN1873-3468
KeywordsAmino Acid Sequence, Bacterial Outer Membrane Proteins, Escherichia coli Proteins, Lipid Bilayers, Membrane Transport Proteins, Models, Molecular, Molecular Sequence Data, Protein Multimerization, Protein Refolding, Protein Structure, Quaternary, Protein Structure, Secondary, Sequence Alignment, Sequence Homology, Amino Acid, Synechocystis
Abstract

Compared to thylakoid and inner membrane proteins in cyanobacteria, no structure-function information is available presently for integral outer-membrane proteins (OMPs). The Slr1270 protein from the cyanobacterium Synechocystis 6803, over-expressed in Escherichia coli, was refolded, and characterized for molecular size, secondary structure, and ion-channel function. Refolded Slr1270 displays a single band in native-electrophoresis, has an α-helical content of 50-60%, as in E. coli TolC with which it has significant secondary-structure similarity, and an ion-channel function with a single-channel conductance of 80-200pS, and a monovalent ion (K(+):Cl(-)) selectivity of 4.7:1. The pH-dependence of channel conductance implies a role for carboxylate residues in channel gating, analogous to that in TolC.

DOI10.1016/j.febslet.2014.08.028
Alternate JournalFEBS Lett.
PubMed ID25218435
PubMed Central IDPMC4288923
Grant ListGM-038323 / GM / NIGMS NIH HHS / United States
P30 DK063491 / DK / NIDDK NIH HHS / United States
R56 GM038323 / GM / NIGMS NIH HHS / United States
R01 GM038323 / GM / NIGMS NIH HHS / United States
P30 CA023168 / CA / NCI NIH HHS / United States