Chemotaxis in Escherichia coli: Methylation of che gene products

AUTOR(ES)

Silverman, Michael

RESUMO

The products of three chemotaxis-specific genes in Escherichia coli, cheM, cheD, and cheZ, are methylated. The cheZ 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 and cheW, are required for the methylation of the cheD and cheM gene products.

Documentos Relacionados

• Roles of cheY and cheZ gene products in controlling flagellar rotation in bacterial chemotaxis of Escherichia coli.
• The smaller of two overlapping cheA gene products is not essential for chemotaxis in Escherichia coli.
• cheA, cheB, and cheC genes of Escherichia coli and their role in chemotaxis.
• Structural studies of methyl-accepting chemotaxis proteins of Escherichia coli: evidence for multiple methylation sites.
• Interaction of the cheC and cheZ gene products is required for chemotactic behavior in Escherichia coli.