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Cysteinyl‐tRNA synthetase is a direct descendant of the first aminoacyl‐tRNA synthetase
Author(s) -
Avalos Javier,
Corrochano Luis M.,
Brenner Sydney
Publication year - 1991
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(91)80968-9
Subject(s) - biology , transfer rna , aminoacyl trna synthetase , biochemistry , neurospora crassa , gene , enzyme , amino acid , neurospora , mutant , microbiology and biotechnology , rna
The gene encoding the cysteinyl‐tRNA synthetase of E. coli was cloned from an E. coli genomic library made in λ2761, a lambda vector which can integrate and which carries a chloramphenicol resistance gene. A thermosensitive cysS mutant of E. coli was lysogenised and chloramphenicol‐resistant colonies able to grow at 42°C were selected to isolate phages containing the wild‐type cysS gene. The sequence of the gene was determined. It codes for a 461 amino‐acid protein and includes the sequences HIGH and KMSK known to be involved in the ATP and TRNA binding respectively of class I synthetases. The cysteinyl enzyme has segments in common with the cytoplasmic leucyl‐tRNA synthetase of Neurospora crassa , the tryptophanyl‐tRNA synthetase of Bacillus stearothermophilus , and the phenylalanyl‐tRNA synthetase of Saccharomyces cerevisiae . Sequence comparisons show that the amino end of the cysteinyl‐tRNA synthetase has similarities with prokaryotic elongation factors Tu; this region is close to the equivalent acceptor binding domain of the glutaminyl‐tRNa synthetase of E. coli . There is a further similarity with the seryl enzyme (a class II enzyme) which has led us to propose that both classes had a common origin and that this was the ancestor of the cysteinyl‐tRNA synthetase.