Novel methyl transfer during chemotaxis in Bacillus subtilis

Thoelke, Mark; Kirby, John R.; Ordal, George

doi:10.1021/bi00439a037

Cited by 41 publications

(59 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, when B. subtilis cells are stimulated with a chemoeffector during a perfusion assay, they release methanol after an attractant is added and after it is removed (45). Furthermore, taxis to glucose, a phosphotransferase substrate, is associated with methanol release in B. subtilis cells in contrast to E. coli cells (44).…”

mentioning

confidence: 99%

Role of methylation in aerotaxis in Bacillus subtilis

et al. 1995

View full text Add to dashboard Cite

Taxis to oxygen (aerotaxis) in Bacillus subtilis was characterized in a capillary assay and in a temporal assay in which the concentration of oxygen in a flow chamber was changed abruptly. A strong aerophilic response was present, but there was no aerophobic response to high concentrations of oxygen. Adaptation to a step increase in oxygen concentration was impaired when B. subtilis cells were depleted of methionine to prevent methylation of the methyl-accepting chemotaxis proteins. There was a transient increase in methanol release when wildtype B. subtilis, but not a cheR mutant that was deficient in methyltransferase activity, was stimulated by a step increase or a step decrease in oxygen concentration. The methanol released was quantitatively correlated with demethylation of methyl-accepting chemotaxis proteins. This indicated that methylation is involved in aerotaxis in B. subtilis in contrast to aerotaxis in Escherichia coli and Salmonella typhimurium, which is methylation independent.Aerotaxis, the migratory response towards or away from oxygen, is a universal property of motile bacteria that enables the bacteria to move to a concentration of dissolved oxygen that is optimal for their preferred metabolism (4, 42). The attraction to oxygen requires the electron transport system and is coincident with changes in the proton motive force (18,19,36).In a homogeneous environment, Escherichia coli, Salmonella typhimurium, and Bacillus subtilis exhibit random walk motility: periods of smooth swimming interrupted periodically by tumbles, or chaotic movements that reorient the cell (6). Favorable stimuli, such as increasing attractant concentrations or decreasing repellent concentrations, reduce the probability of tumbling, thereby extending bacterial travel in the favorable direction. In a temporal assay, these bacteria respond to a step increase in attractant concentration by suppressing tumbling and swimming smoothly and to a step decrease in attractant concentration by continuous tumbling (23, 46) (for a review of chemotaxis, see references 7, 22, 24, and 43).Both E. coli and S. typhimurium adapt to an increased concentration of attractant by restoring random swimming behavior. Adaptation to attractant occurs when the CheR protein, a chemotaxis-specific methyltransferase (39), transfers a methyl group from S-adenosylmethionine (17) to the ␥-carboxyl group of glutamyl residues on the transmembrane chemotaxis receptor (MCP) (38, 48). Adaptation to an increased concentration of repellent occurs when the CheB protein, a methylesterase, hydrolyzes the glutamyl methyl esters to liberate methanol (41). The production of methanol can be followed by a perfusion assay that measures the time course of methanol release from bacteria during chemotaxis (14). An attractant added to E. coli cells inhibits methanol release during adaptation to the attractant, and removal of the attractant enhances methanol release during adaptation to the unfavorable (repellent) stimulus.In contrast to methylation-dependent chemotaxis in which ...

show abstract

mentioning

confidence: 99%

Role of methylation in aerotaxis in Bacillus subtilis

et al. 1995

View full text Add to dashboard Cite

show abstract

“…We have reported previously that the mechanism of chemotaxis in Bacillus subtilis is different in some respects from that observed in E. coli and S. typhimurium; the differences appear to be in the role that methyl transfer plays in excitation and adaptation (33)(34)(35). To characterize these differences further, we have been isolating and studying chemotaxis mutants (28,29).…”

mentioning

confidence: 99%

Nucleotide sequence and characterization of a Bacillus subtilis gene encoding a flagellar switch protein

1991

View full text Add to dashboard Cite

The nucleotide sequence of the Bacillus subtilisfliM gene has been determined. This gene encodes a 38-kDa protein that is homologous to the FliM flagellar switch proteins of Escherichia coli and SalmoneUa typhimurium. gene cannot complement an E. colifliM mutant. A frameshift mutation was constructed in thefJl gene, and the mutation was transferred onto the B. subtilis chromosome. The mutant has a Fla-phenotype. This phenotype is consistent with the hypothesis that the FliM protein encodes a component of the flagellar switch in B. subtilis. Additional characterization of the fliM mutant suggests that the hag and mot loci are not expressed. These loci are regulated by the SigD form of RNA polymerase. We also did not observe any methyl-accepting chemotaxis proteins in an in vivo methylation experiment. The expression of these proteins is also dependent upon SigD. It is possible that a functional basal body-hook complex may be required for the expression of SigD-regulated chemotaxis and motility genes.

show abstract

“…OI1085 is a chemotactic wild-type strain of B. subtilis which has been previously described (35 (33).…”

Section: Methodsmentioning

confidence: 99%

“…Protoplasts were solubilized by boiling for 5 min in 2x sodium dodecyl sulfate (SDS) solubilization buffer, and then they were applied to SDS-polyacrylamide gels (10% polyacrylamide) (33). Gels were prepared for fluorography as previously described (33).…”

Section: Methodsmentioning

confidence: 99%

“…These methyl groups remain in the system, rather than evolving directly as methanol, since they return to the MCPs (32-34) when the attractant is removed. It is believed that these methyl groups are transferred to a regulator protein, but its function is not presently understood (2,(31)(32)(33)(34). Another significant comparison between E. coli and B. subtilis is the switch that controls the direction of flagellar rotation.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Influence of attractants and repellents on methyl group turnover on methyl-accepting chemotaxis proteins of Bacillus subtilis and role of CheW

1992

View full text Add to dashboard Cite

The ability of attractants and repellents to affect the turnover of methyl groups on the methyl-accepting chemotaxis proteins (MCPs) was examined for Bacillus subtilis. Attractants were found to cause an increase in the turnover of methyl groups esterified to the MCPs, while repellents caused a decrease. These reactions do not require CheW. However, a cheW null mutant exhibits enhanced turnover in unstimulated cells. Assuming that the turnover of methyl groups on the MCPs reflects a change in the activity of CheA, these results suggest that the activation of CheA via chemoeffector binding at the receptor does not require CheW.Escherichia coli has been the prototype for understanding chemotactic sensory transduction in bacteria. In E. coli, when a chemoeffector binds to the receptors, or methylaccepting chemotaxis proteins (MCPs), a conformational change occurs in the receptor, which transmits the information from the periplasmic space to the cytoplasm (30). The addition of attractant in the presence of CheW is believed to inhibit the autophosphorylation of CheA such that the level of CheY-P subsequently decreases (7,21). CheY-P is thought to bind to the switch to cause clockwise rotation of the flagella (20,23,27,28,36,37). The addition of attractant also increases the rate of methylation of the MCPs by the methyltransferase (13) CheR such that the rate of CheA autophosphorylation can return to normal (29), thus allowing the bacteria to adapt. Repellents are believed to increase the rate of autophosphorylation of CheA and hence the level of CheY-P (6), inducing the bacteria to tumble. However, CheA-P also phosphorylates CheB, and CheB-P, which is the activated form of the methylesterase (17), rapidly demethylates the MCPs so that CheA-P returns to the prestimulus level (20).Chemotaxis in Bacillus subtilis has significant similarities to as well as differences from chemotaxis in E. coli. For instance, B. subtilis has homologs to CheA (10), CheB (11,19), CheR (8, 9), CheW (14), and CheY (3). CheA in B. subtilis, like that in E. coli, is probably the master controller of chemotaxis, because excitation does not occur in a cheA null mutant (10). However, a novel reaction, whereby attractants cause a high rate of turnover of methyl groups on the MCPs, occurs in B. subtilis. These methyl groups remain in the system, rather than evolving directly as methanol, since they return to the MCPs (32-34) when the attractant is removed. It is believed that these methyl groups are transferred to a regulator protein, but its function is not presently understood (2, 31-34). Another significant comparison between E. coli and B. subtilis is the switch that controls the direction of flagellar rotation. Both organisms have FliM (38) and FliG (1) homologs. In addition, E. coli has a small (14-kDa) protein, FliN (15,18)

show abstract

Novel methyl transfer during chemotaxis in Bacillus subtilis

Cited by 41 publications

References 24 publications

Role of methylation in aerotaxis in Bacillus subtilis

Role of methylation in aerotaxis in Bacillus subtilis

Nucleotide sequence and characterization of a Bacillus subtilis gene encoding a flagellar switch protein

Influence of attractants and repellents on methyl group turnover on methyl-accepting chemotaxis proteins of Bacillus subtilis and role of CheW

Contact Info

Product

Resources

About