Methyltransferase CheR binds to its chemoreceptor substrates independent of their signaling conformation yet modifies them differentially.

ABSTRACT: Methylation of specific chemoreceptor glutamyl residues by methyltransferase CheR mediates sensory adaptation and gradient sensing in bacterial chemotaxis. Enzyme action is a function of chemoreceptor signaling conformation: kinase-off receptors are more readily methylated than kinase-on, a feature central to adaptational and gradient-sensing mechanisms. Differential enzyme action could reflect differential binding, catalysis or both. We investigated by measuring CheR binding to kinase-off and kinase-on forms of Escherichia coli aspartate receptor Tar deleted of its CheR-tethering, carboxyl terminus pentapeptide. This allowed characterization of the low-affinity binding of enzyme to the substrate receptor body, otherwise masked by high-affinity interaction with pentapeptide. We quantified

SUBMITTER: Li M 

PROVIDER: S-EPMC6954704 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature