Mutational analyses of HAMP helices suggest a dynamic bundle model of input-output signalling in chemoreceptors.

ABSTRACT: To test the gearbox model of HAMP signalling in the Escherichia coli serine receptor, Tsr, we generated a series of amino acid replacements at each residue of the AS1 and AS2 helices. The residues most critical for Tsr function defined hydrophobic packing faces consistent with a four-helix bundle. Suppression patterns of helix lesions conformed to the predicted packing layers in the bundle. Although the properties and patterns of most AS1 and AS2 lesions were consistent with both proposed gearbox structures, some mutational features specifically indicate the functional importance of an x-da bundle over an alternative a-d bundle. These genetic data suggest that HAMP signalling could simply involve changes in the stability of its x-da bundle. We propose that Tsr HAMP controls output signals

SUBMITTER: Zhou Q 

PROVIDER: S-EPMC2749569 | biostudies-literature | 2009 Sep

REPOSITORIES: biostudies-literature