Disease relevance of cheB

• We also identify a new gene, frzG, whose predicted product is homologous to that of the cheB (methylesterase) gene from Escherichia coli [1].
• It has previously been reported that the alpha-proteobacterium Azospirillum brasilense undergoes methylation-independent chemotaxis; however, a recent study revealed cheB and cheR genes in this organism [2].

High impact information on cheB

• Analyses of cheR and/or cheB mutants, defective in receptor methylation/demethylation, show that response sensitivity depends on the activity of CheB and the level of receptor modification [3].
• They were both refractory to methylation or to modification of the C-terminal region of the protein by the cheB gene product [4].
• However, a CheB point mutant swims smoothly, even in the presence of a plasmid bearing cheB, which restores the null mutants to wild type [5].
• The nucleotide sequence of the cheB gene predicts a 349-amino acid protein with cysteine residues at positions 207 and 309 [6].
• We have constructed cheB, cheR, and cheBR mutants of A. brasilense and determined that the CheB and CheR proteins under study significantly influence chemotaxis and aerotaxis but are not essential for these behaviors to occur [2].

Biological context of cheB

• Deletion of the entire che operon (delta che), as well as nonpolar disruptions of cheAY, cheW, and cheR, resulted in a smooth-swimming phenotype, whereas disruption of cheB resulted in a locked tumbly phenotype [7].
• Second, in comparison to the wild type, cheB and cheR mutants under steady-state conditions exhibited an altered swimming bias, whereas the cheBR mutant and the che operon mutant did not [2].

Associations of cheB with chemical compounds

• In comparison to the wild type, the cheB, cheR, and cheBR mutants showed various altered patterns of methanol release upon exposure to attractants [2].

Other interactions of cheB

• To express this synthetic gene in Escherichia coli, an expression vector, pJC264, was constructed by inserting portions of the E. coli cheB and cheY gene complex into the plasmid pUC13 [8].

References