Open AccessChemotaxis in Escherichia coli : Methylation of che gene products
Author(s) -
Melvin Silverman,
Melvin I. Simon
Publication year - 1977
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.74.8.3317
Subject(s) - mutant , escherichia coli , chemotaxis , gene , methylation , biology , biochemistry , chemistry , microbiology and biotechnology , receptor
The products of three chemotaxis-specific genes inEscherichia coli, cheM, cheD , andcheZ , are methylated. ThecheZ gene codes for the synthesis of a 24,000 molecular weight polypeptide that appears in the cytoplasm.cheM codes for the synthesis of a membrane-bound polypeptide with a molecular weight of 61,000.cheD codes for another membrane-bound polypeptide with an apparent molecular weight of 64,000. CheM- mutants show chemotaxis toward some attractants (Tar- phenotype), while CheD- mutants respond to other attractants (Tsr- phenotype). The double mutant (CheD- , CheM- ) does not respond to any attractant or repellent tested. Therefore, these polypeptides play a central role in chemotaxis. They collect information from two subsets of chemoreceptors and act as the last step in the chemoreceptor pathway and the first step in the general processing of signals for transmission to the flagellar rotor. It is suggested that they may be involved in both an initial process that reflects the instantaneous state of the chemoreceptors and in an integrative, adaptive process. Two other genes,cheX andcheW , are required for the methylation of thecheD andcheM gene products.