Chitoporin from the Marine Bacterium Vibrio harveyi: PROBING THE ESSENTIAL ROLES OF TRP136 AT THE SURFACE OF THE CONSTRICTION ZONE.

ABSTRACT: VhChiP is a sugar-specific porin present in the outer membrane of the marine bacterium Vibrio harveyi. VhChiP is responsible for the uptake of chitin oligosaccharides, with particular selectivity for chitohexaose. In this study, we employed electrophysiological and biochemical approaches to demonstrate that Trp(136), located at the mouth of the VhChiP pore, plays an essential role in controlling the channel's ion conductivity, chitin affinity, and permeability. Kinetic analysis of sugar translocation obtained from single channel recordings indicated that the Trp(136) mutations W136A, W136D, W136R, and W136F considerably reduce the binding affinity of the protein channel for its best substrate, chitohexaose. Liposome swelling assays confirmed that the Trp(136) mutations decreased the rate o

SUBMITTER: Chumjan W 

PROVIDER: S-EPMC4521040 | biostudies-literature | 2015 Jul

REPOSITORIES: biostudies-literature