User:Miaomin Zhang/Sandbox 1

From Proteopedia

Revision as of 15:39, 3 May 2011

One of the CBI Molecules being studied in the University of Massachusetts Amherst Chemistry-Biology Interface Program at UMass Amherst and on display at the Molecular Playground.

S-adenosylmethionine-dependent protein methyltransferase, CheR

Molecular Playground Banner: CheR, the protein that reactivates numb bacterial "noses"

Bacteria such as Salmonella typhimurium use chemotaxis system to swim towards neutrients and other attractants. At the forefront of the chemotaxis system are a set of transmembrane proteins called chemoreceptors. They sense the chemical environment and trigger the chemotaxis signal transduction pathway, which eventually affect the flagella motors, causing bacteria to either keep moving up the gradient (if they are on the right track) or stumble to change directions. However, the binding between attractants and chemoreceptors also suppresses the receptor activity and reduces the tumbling frequency. An adaptation mechanism is therefore needed to restore chemoreceptors' activity to elicit flagella responses. This, as one would expect in signal transduction processes, is provided by reversible methylation of specific glutamate residues in the chemoreceptors' cytoplasmic domains, where methylation is catalyzed by S-adenosylmethionine-dependent protein methyltransferase, CheR.

CheR binds to a specific sequence at the C-termini of chemoreceptors and methylates neighboring

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