title: Stabilization of the ternary complex EF-Tu.GTP.valyl-tRNAval by ammonium salts.
abstract: In a search for crystallizing conditions for the ternary complex EF-Tu.GTP.valyl-tRNAval, the influence of various salts on its stability has been examined by measuring the rate of deacylation of the aminoacyl-tRNA in the complex. The most striking result is the general higher stability in solutions of ammonium salts and, in particular, the enhancement of this effect by sulphate and citrate. Thus sodium sulphate and citrate lead to destabilization of the complex, as expected from conventional considerations of adding salt, whereas the corresponding ammonium salts stabilize the complex as shown, for example, by an increase in the half-life of the valyl-tRNAval in the complex from about 20 hours to at least 300 hours in the presence of 1.2 M ammonium sulphate. These results suggest that ammonium sulphate and ammonium citrate might be very suitable precipitants for crystallization studies of the ternary complex.
mesh_terms: D003460:Crystallization; D004926:Escherichia coli; D006160:Guanosine Triphosphate / Q000378:metabolism*; D006207:Half-Life; D046911:Macromolecular Substances; D010444:Peptide Elongation Factor Tu; D010445:Peptide Elongation Factors / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism*
chemical_list: D046911:Macromolecular Substances; D010445:Peptide Elongation Factors; D000644:Quaternary Ammonium Compounds; D012346:RNA, Transfer, Amino Acyl; D006160:Guanosine Triphosphate; D010444:Peptide Elongation Factor Tu