Analysis of gating transitions among the three major open states of the OpdK channel

Belete R. Cheneke, Bert Van Den Berg, Liviu Movileanu

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

OpdK is an outer membrane protein of the pathogenic bacterium Pseudomonas aeruginosa. The recent crystal structure of this protein revealed a monomeric, 18-stranded β-barrel with a kidney-shaped pore, whose constriction features a diameter of 8 Å. Using systematic single-channel electrical recordings of this protein pore reconstituted into planar lipid bilayers under a broad range of ion concentrations, we were able to probe its discrete gating kinetics involving three major and functionally distinct conformations, in which a dominant open substate O2 is accompanied by less thermodynamically stable substates O1 and O3. Single-channel electrical data enabled us to determine the alterations in the energetics and kinetics of the OpdK protein when experimental conditions were changed. In the future, such a semiquantitative analysis might provide a better understanding on the dynamics of current fluctuations of other β-barrel membrane protein channels.

Original languageEnglish (US)
Pages (from-to)4987-4997
Number of pages11
JournalBiochemistry
Volume50
Issue number22
DOIs
StatePublished - Jun 7 2011

ASJC Scopus subject areas

  • Biochemistry

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