The identification of a domain in Escherichia coli elongation factor Tu that interacts with elongation factor Ts.
A method has been developed to search for the elongation factor Tu (EF-Tu) domain(s) that interact with elongation factor Ts (EF-Ts). This method is based on the suppression of Escherichia coli EF-Tu-dominant negative mutation K136E, a mutation that exerts its effect by sequestering EF-Ts. We have identified nine single-amino acid- substituted suppression mutations in the region 146-199 of EF-Tu. These mutations are R154C, P168L, A174V, K176E, D181G, E190K, D196G, S197F, and I199V. All suppression mutations but one (R154C) significantly affect EF-Tu's ability to interact with EF-Ts under equilibrium conditions. Moreover, with the exception of mutation A174V, the GDP affinity of EF-Tu appears to be relatively unaffected by these mutations. These results suggest that the domain of residues 154 to 199 on EF-Tu is involved in interacting with EF-Ts. These suppression mutations are also capable of suppressing dominant negative mutants N135D and N135I to various degrees. This suggests that dominant negative mutants N135D and N135I are likely to have the same molecular basis as the K136E mutation. The method we have developed in this study is versatile and can be readily adapted to map other regions of EF-Tu. A model of EF-Ts-catalyzed guanine-nucleotide exchange is discussed.
Hwang
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YW
Molecular Biology Department, New York State Institute for Basic Research in Developmental Disabilities, Staten Island 10314.
Carter
M
M
Miller
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DL
D000595:Amino Acid Sequence; D001483:Base Sequence; D004926:Escherichia coli; D020963:GTP Phosphohydrolase-Linked Elongation Factors / Q000737:chemistry; D019204:GTP-Binding Proteins / Q000737:chemistry*; D016153:Genes, Suppressor; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D010444:Peptide Elongation Factor Tu / Q000737:chemistry*; D010445:Peptide Elongation Factors / Q000737:chemistry*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
D009838:Oligodeoxyribonucleotides; D010445:Peptide Elongation Factors; C023512:elongation factor Ts; D020963:GTP Phosphohydrolase-Linked Elongation Factors; D019204:GTP-Binding Proteins; D010444:Peptide Elongation Factor Tu