HAMP domain structural determinants for signalling and sensory adaptation in Tsr, the Escherichia coli serine chemoreceptor.

ABSTRACT: HAMP domains mediate input-output transactions in many bacterial signalling proteins. To clarify the mechanistic logic of HAMP signalling, we constructed Tsr-HAMP deletion derivatives and characterized their steady-state signal outputs and sensory adaptation properties with flagellar rotation and receptor methylation assays. Tsr molecules lacking the entire HAMP domain or just the HAMP-AS2 helix generated clockwise output signals, confirming that kinase activation is the default output state of the chemoreceptor signalling domain and that attractant stimuli shift HAMP to an overriding kinase-off signalling state to elicit counter-clockwise flagellar responses. Receptors with deletions of the AS1 helices, which free the AS2 helices from bundle-packing constraints, exhibited kinase-off signa

SUBMITTER: Ames P 

PROVIDER: S-EPMC4154141 | biostudies-literature | 2014 Mar

REPOSITORIES: biostudies-literature