title: Effect of Thermus thermophilus elongation factor Ts on the conformation of elongation factor Tu.
abstract: Affinity labeling in situ of the Thermus thermophilus elongation factor Tu (EF-Tu) nucleotide binding site was achieved with periodate-oxidized GDP (GDPoxi) or GTP (GTPoxi) in the absence and presence of elongation factor Ts (EF-Ts). Lys52 and Lys137, both reacting with GDPoxi and GTPoxi, are located in the nucleotide binding region. In the absence of EF-Ts Lys137 and to a lesser extent Lys52 were accessible to the reaction with GTPoxi. GDPoxi reacted much more efficiently with Lys52 than with Lys137 under these conditions [Peter, M. E., Wittman-Liebold, B. & Sprinzl, M. (1988) Biochemistry 27, 9132-9138]. In the presence of EF-Ts, GDPoxi reacted more efficiently with Lys137 than with Lys52, indicating that the interaction of EF-Ts with EF-Tu.GDPoxi induces a conformation resembling that of the EF-Tu.GDPoxi complex in the absence of EF-Ts. Binding of EF-Ts to EF-Tu.GDP enhances the accessibility of the Arg59-Gly60 peptide bond of EF-Tu to trypsin cleavage. Hydrolysis of this peptide bond does not interfere with the ability of EF-Ts to bind to EF-Tu. EF-Ts is protected against trypsin cleavage by interaction with EF-Tu.GDP. High concentrations of EF-Ts did not interfere significantly with aminoacyl-tRNA.EF-Tu.GTP complex formation.
authors.affiliation: Laboratorium für Biochemie, Universität Bayreuth, Federal Republic of Germany.
authors.forename: N K
authors.initials: NK
authors.lastname: Schirmer
authors.forename: C O
authors.initials: CO
authors.lastname: Reiser
authors.forename: M
authors.initials: M
authors.lastname: Sprinzl
mesh_terms: D000345:Affinity Labels; D001665:Binding Sites; D004591:Electrophoresis, Polyacrylamide Gel; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006868:Hydrolysis; D010084:Oxidation-Reduction; D010444:Peptide Elongation Factor Tu / Q000737:chemistry / Q000378:metabolism*; D010445:Peptide Elongation Factors / Q000378:metabolism*; D011487:Protein Conformation; D013050:Spectrometry, Fluorescence; D013824:Thermus / Q000378:metabolism*; D014357:Trypsin
chemical_list: D000345:Affinity Labels; D010445:Peptide Elongation Factors; C023512:elongation factor Ts; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate; D014357:Trypsin; D010444:Peptide Elongation Factor Tu