Mutational analysis of the transmembrane helix 2-HAMP domain connection in the Escherichia coli aspartate chemoreceptor tar.

ABSTRACT: Transmembrane helix 2 (TM2) of the Tar chemoreceptor undergoes an inward piston-like displacement of 1 to 3 Å upon binding aspartate. This signal is transmitted to the kinase-control module via the HAMP domain. Within Tar, the HAMP domain forms a parallel four-helix bundle consisting of a dimer of two amphipathic helices connected by a flexible linker. In the nuclear magnetic resonance structure of an archaeal HAMP domain, residues corresponding to the MLLT sequence between Arg-214 at the end of TM2 and Pro-219 of Tar are an N-terminal helical extension of AS1. We modified this region to test whether it behaves as a continuous helical connection between TM2 and HAMP. First, one to four Gly residues were inserted between Thr-218 and Pro-219. Second, the MLLT sequence was replaced with one t

SUBMITTER: Wright GA 

PROVIDER: S-EPMC3019941 | biostudies-literature | 2011 Jan

REPOSITORIES: biostudies-literature