A possible degree of motional freedom in bacterial chemoreceptor cytoplasmic domains and its potential role in signal transduction.

ABSTRACT: We describe an array of gaps in an antiparallel four-helix bundle structure, the cytoplasmic domains of bacterial chemoreceptors. For a given helix, the side chain interactions that define a helix's position are analyzed in terms of residue interfaces, the most important of which are a-a, g-g, d-d, g-d, and a-d. It was found that the interdigitation of the side groups does not entirely fill the space along the long axis of the structure, which results in a rather regular array of gaps. A simulated piston motion of helix CD1 along the helical axis direction by 1.2Å shows that 85% of the side chain interactions still satisfy Van der Waals criteria, while the remaining clashes could be avoided by small rotations of side chains. Therefore, two states could exist in the structure, related by a

SUBMITTER: Hu W 

PROVIDER: S-EPMC3180096 | biostudies-literature | 2011

REPOSITORIES: biostudies-literature