Gain-of-function mutations cluster in distinct regions associated with the signalling pathway in the PAS domain of the aerotaxis receptor, Aer.

ABSTRACT: The Aer receptor monitors internal energy (redox) levels in Escherichia coli with an FAD-containing PAS domain. Here, we randomly mutagenized the region encoding residues 14-119 of the PAS domain and found 72 aerotaxis-defective mutants, 24 of which were gain-of-function, signal-on mutants. The mutations were mapped onto an Aer homology model based on the structure of the PAS-FAD domain in NifL from Azotobacter vinlandii. Signal-on lesions clustered in the FAD binding pocket, the beta-scaffolding and in the N-cap loop. We suggest that the signal-on lesions mimic the 'signal-on' state of the PAS domain, and therefore may be markers for the signal-in and signal-out regions of this domain. We propose that the reduction of FAD rearranges the FAD binding pocket in a way that repositions the bet

SUBMITTER: Campbell AJ 

PROVIDER: S-EPMC2916861 | biostudies-literature | 2010 Aug

REPOSITORIES: biostudies-literature