Conformational Motions and Functionally Key Residues for Vitamin B12 Transporter BtuCD-BtuF Revealed by Elastic Network Model with a Function-Related Internal Coordinate.

ABSTRACT: BtuCD-BtuF from Escherichia coli is a binding protein-dependent adenosine triphosphate (ATP)-binding cassette (ABC) transporter system that uses the energy of ATP hydrolysis to transmit vitamin B12 across cellular membranes. Experimental studies have showed that during the transport cycle, the transporter undergoes conformational transitions between the "inward-facing" and "outward-facing" states, which results in the open-closed motions of the cytoplasmic gate of the transport channel. The opening-closing of the channel gate play critical roles for the function of the transporter, which enables the substrate vitamin B12 to be translocated into the cell. In the present work, the extent of opening of the cytoplasmic gate was chosen as a function-related internal coordinate. Then the mean-sq

SUBMITTER: Su JG 

PROVIDER: S-EPMC4581229 | biostudies-literature | 2015 Aug

REPOSITORIES: biostudies-literature