Defects in the nutrient-dependent methylation of a membrane-associated protein in spo mutants of Bacillus subtilis

Chemotaxis, sporulation, and larvicide production in Bacillus sphaericus 2362. The influence of L-ethionine, and of aminophenylboronic acid

4-Aminophenylboronic acid (APBA), a known inhibitor of sporulation in Bacilli, as well as L-ethionine, a known inhibitor of chemotaxis in Enterobacteria, inhibited both sporulation and chemotactic behavior but not growth of Bacillus sphaericus. Both compounds also inhibited the methyl group turnover on the methyl-accepting chemotaxis protein (P53) in this microorganism. Sporulation of B. sphaericus was inhibited only when APBA was added to the growing culture before the late logarithmic stage. It was previously demonstrated that the ability of B. sphaericus to respond to chemoattractants sharply declines at the same age of the culture. Thus, it seems plausible that the action of both inhibitors upon sporulation may be attributed to the inhibition of some regulatory pathway common to chemotaxis and sporulation and involving protein methylation. Possible exchange of the nutrient depletion-related sensory information between chemotaxis and sporulation systems at the level of methyl group transfer is discussed.

Chemotaxis, sporulation, and larvicide production in Bacillus sphaericus 2362. The influence of L-ethionine, and of aminophenylboronic acid

4-Aminophenylboronic acid (APBA), a known inhibitor of sporulation in Bacilli, as well as L-ethionine, a known inhibitor of chemotaxis in Enterobacteria, inhibited both sporulation and chemotactic behavior but not growth of Bacillus sphaericus. Both compounds also inhibited the methyl group turnover on the methyl-accepting chemotaxis protein (P53) in this microorganism. Sporulation of B. sphaericus was inhibited only when APBA was added to the growing culture before the late logarithmic stage. It was previously demonstrated that the ability of B. sphaericus to respond to chemoattractants sharply declines at the same age of the culture. Thus, it seems plausible that the action of both inhibitors upon sporulation may be attributed to the inhibition of some regulatory pathway common to chemotaxis and sporulation and involving protein methylation. Possible exchange of the nutrient depletion-related sensory information between chemotaxis and sporulation systems at the level of methyl group transfer is discussed.

Elongation factor Tu is methylated in response to nutrient deprivation in Escherichia coli

It has been shown previously that starvation of a mid-logarithmic-phase culture of Escherichia coli B/r for an essential nutrient results in the methylation of a membrane-associated protein (P-43) (C. C. Young and R. W. Bernlohr, J. Bacteriol. 172:5147-5153, 1990). In this communication, the purification of P-43 and sequence analysis of cyanogen bromide-generated peptide fragments identified P-43 as elongation factor Tu (EF-Tu). This was confirmed by the ability of anti-EF-Tu antibody to precipitate P-43. We propose that the nutrient-dependent methylation of EF-Tu may be involved in the regulation of growth, possibly as a principal component of an unidentified signal transduction pathway in bacteria.

Nutrient-dependent methylation of a membrane-associated protein of Escherichia coli

Starvation of a mid-log-phase culture of Escherichia coli B/r for nitrogen, phosphate, or carbon resulted in methylation of a membrane-associated protein of about 43,000 daltons (P-43) in the presence of chloramphenicol and [methyl-3H]methionine. The in vivo methylation reaction occurred with a doubling time of 2 to 5 min and was followed by a slower demethylation process. Addition of the missing nutrient to a starving culture immediately prevented further methylation of P-43. P-43 methylation is not related to the methylated chemotaxis proteins because P-43 is methylated in response to a different spectrum of nutrients and because P-43 is methylated on lysine residues. The characteristics of P-43 are similar to those of a methylated protein previously described in Bacillus subtilis and B. licheniformis (R. W. Bernlohr, A. L. Saha, C. C. Young, B. R. Toth, and K. J. Golden, J. Bacteriol. 170:4113-4118, 1988; K. J. Golden and R. W. Bernlohr, Mol. Gen. Genet. 220:1-7, 1989) and are consistent with the proposal that methylation of this protein functions in nutrient sensing.