J. Biol. Chem., Vol. 261, Issue 25, 11448-11451, 09, 1986
Stimulation of Escherichia coli adenylate cyclase activity by elongation factor Tu, a GTP-binding protein essential for protein synthesis
P Reddy, D Miller and A Peterkofsky
A unique feature of eucaryotic adenylate cyclases is their interaction with
GTP-binding proteins that mediate hormonal responses. Until now, there has
been no evidence for regulation of Escherichia coli adenylate cyclase by a
GTP-binding protein. We describe here that the most abundant protein in E.
coli, the GTP-binding protein EF-Tu, which is important as an elongation
factor in protein synthesis, also serves as a stimulator of adenylate
cyclase activity. Homogeneous EF-Tu specifically increased the activity of
purified adenylate cyclase as much as 70%; other E. coli GTP-binding
proteins had no effect on enzyme activity. A study of the guanine
nucleotide specificity for EF-Tu- mediated stimulation of adenylate cyclase
activity suggested that the preferred activator is EF-Tu X GDP. To account
for the GTP-specific stimulation of adenylate cyclase activity observed in
intact cells, we propose that the nucleotide specificity for
EF-Tu-dependent activation of adenylate cyclase is governed by other
factors in the cell.