Identification of a site of ATP requirement for signal processing in bacterial chemotaxis

Abstract

. Chem. 257:7969-7975, 1982). The site of the ATP requirement was investigated. The times required for S. typhimurium ST23 (hisF) to adapt to a step increase in serine, phenol, or benzoate were similar in cells depleted of ATP and in cells with normal levels of ATP. This established that ATP was not required for the chemotactic signal to cross the inner membrane or for adaptation to the transmembrane signal to occur. Depletion of ATP did not affect the probability of clockwise rotation in E. coli cheYZ scy strains that were defective in the cheY and cheZ genes and had a partially compensating mutation in the motor switch. Strain HCB326 (cheAWRBYZ tar tap tsr trg::TnlO), which was deficient in all chemotaxis components except the switch and motor, was transformed with the pCK63 plasmid (ptac-cheY+). Induction of cheY in the transformant increased the frequency of clockwise rotation, but except at the highest levels of CheY overproduction, clockwise rotation was abolished by depleting ATP. It is proposed that the CheY protein is normally in an inactive form and that ATP is required for formation of an active CheY* protein that binds to the switch on the flagellar motors and initiates clockwise rotation. Depletion of ATP partially inhibits feedback regulation of the cheB product, protein methylesterase, but this may reflect a second site of ATP action in chemotaxis.

Signal transduction in chemotaxis to oxygen in Escherichia coli and Salmonella typhimurium

“…Recent investigations of the basis for an ATP requirement (27,30) in chemotaxis revealed a protein transphosphorylation mechanism that may be the signal transduction pathway (11). The cheA gene product is autophosphorylated, and the phosphoryl residue can be transferred to the che Y gene product (10,36 …”

Multiple kinetic states for the flagellar motor switch

“…In previous studies, it has been generally assumed that no CheA or CheZ functions remain in this deletion, since the deletion mutant does not complement either cheA or cheZ mutants. However, the existence of residual kinase activity leaves unresolved the question of whether unphosphorylated CheY can be effective in inducing clockwise rotation (10,20,39,45). It also provides an alternative explanation for the effect of arsenate poisoning on CheY-induced reversals in this strain (39).…”

“…5 (20), there was the possibility that the A/Z fusion protein retains kinase activity. This deletion has been the basis for numerous studies of "gutted" strains that lack any chemotaxis functions (10,20,39,45). Although A(cheAcheZ)2209 has not been sequenced, deletion mapping indicates that the A/Z fusion protein retains approximately seven-eighths of CheA (32) and is larger than wild-type CheA because of additional CheZ sequences (20).…”

N-terminal half of CheB is involved in methylesterase response to negative chemotactic stimuli in Escherichia coli

“…Hess and coworkers have recently provided direct evidence for such interactions by demonstrating phosphorylation of CheB and CheY by CheA (15,16,31). These phosphotransfer reactions may provide a mechanism for modulating CheB methylesterase activity in response to chemostimuli and for activating CheY as a tumble generator (15,16,31,34,45). The sequence homology between CheY and the N-terminal portion of CheB and analogies with other bacterial sensory systems (18a, 38, 52) suggest that the site of CheB phosphorylation lies in its N-terminal half.…”