Molecular cloning and sequencing ofinfC, the gene encoding translation initiation factor IF3, from four enterobacterial species

Translation initiation factor IF3 plays a crucial role in initiation of protein synthesis in bacteria. In order to elucidate the IF3 structural elements required for these functions, the evolutionary conservation of IF3 and its gene, infC, was investigated. Homologous infC sequences from Salmonella typhimurium, Klebsiella pneumoniae, Serratia marcescens and Proteus vulgaris were amplified by the polymerase chain reaction and sequenced. Analysis of these sequences, as well as that from Bacillus stearothermophilus, revealed several regions (e.g. residues 62-73 and 173-177) of absolute sequence conservation, suggesting an important role for these regions in IF3 function.