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Genetic analysis of response regulator activation in bacterial chemotaxis suggests an intermolecular mechanism
Author(s) -
Re Sandra Da,
Tolstykh Tatiana,
Wolanin Peter M.,
Stock Jeffry B.
Publication year - 2002
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.0220402
Subject(s) - chemotaxis , regulator , mechanism (biology) , intermolecular force , response regulator , master regulator , chemistry , microbiology and biotechnology , biology , biophysics , genetics , bacterial protein , bacteria , gene , physics , transcription factor , receptor , organic chemistry , quantum mechanics , molecule
Abstract Response regulator proteins of two‐component systems are usually activated by phosphorylation. The phosphorylated response regulator protein CheY∼P mediates the chemotaxis response in Escherichia coli . We performed random mutagenesis and selected CheY mutants that are constitutively active in the absence of phosphorylation. Although a single amino acid substitution can lead to constitutive activation, no single DNA base change can effect such a transition. Numerous different sets of mutations that activate in synergy were selected in several different combinations. These mutations were all located on the side of CheY defined by α4, β5, α5, and α1. Our findings argue against the two‐state hypothesis for response regulator activation. We propose an alternative intermolecular mechanism that involves a dynamic interplay between response regulators and their effector targets.