title: Stimulation of Escherichia coli adenylate cyclase activity by elongation factor Tu, a GTP-binding protein essential for protein synthesis.
abstract: 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.
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000494:pharmacology; D007700:Kinetics; D008954:Models, Biological; D010444:Peptide Elongation Factor Tu / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism
chemical_list: D011956:Receptors, Cell Surface; D006160:Guanosine Triphosphate; D019204:GTP-Binding Proteins; D010444:Peptide Elongation Factor Tu; D000262:Adenylyl Cyclases