Methylation in vivo of elongation factor EF-Tu at lysine-56 decreases the rate of tRNA-dependent GTP hydrolysis
Article first published online: 3 MAR 2005
European Journal of Biochemistry
Volume 160, Issue 3, pages 557–561, November 1986
How to Cite
VAN NOORT, J. M., KRAAL, B., SINJORGO, K. M. C., PERSOON, N. L. M., JOHANNS, E. S. D. and BOSCH, L. (1986), Methylation in vivo of elongation factor EF-Tu at lysine-56 decreases the rate of tRNA-dependent GTP hydrolysis. European Journal of Biochemistry, 160: 557–561. doi: 10.1111/j.1432-1033.1986.tb10074.x
- Issue published online: 3 MAR 2005
- Article first published online: 3 MAR 2005
- (Received June 26, 1986) – EJB 86 0686
In this paper we show, that the in vivo methylation of the elongation factor Tu from Escherichia coli is correlated with the growth phase of the bacterium. Methylation occurs at one position only, i.e. Lys-56, and initially results in monomethylation during logarithmic growth. Upon entering the stationary phase of E. coli, monomethyllysine is gradually converted into dimethyllysine.
We have undertaken an extensive comparison between the properties of the highly methylated EF-Tu and unmodified EF-Tu. No gross conformational differences, as measured by the rate of mild tryptic cleavage, were observed. The dissociation rates of the nucleotides GDP and GTP appear likewise to be unaffected by the methylation, just as is the stimulatory effect of the elongation factor Ts upon these rates. Whereas tRNA binding at the classical binding site of EF-Tu (site I) also appears not to be affected by the methylation of the protein. tRNA binding at site II is. Although the apparent affinity of tRNA for site II remains unaltered upon methylation of EF-Tu, the conformational effects of tRNA binding at this site become different. Both the GTPase activity of the protein and the reactivity of Cys-81 are significantly less stimulated by the tRNA when EF-Tu is methylated.
A possible physiological implication of this phenomenon is discussed.