Chromosomal location and structure of the operon encoding peptide-chain-release factor 2 of Escherichia coli.
Abstract
The prfB gene encodes peptide-chain-release factor 2 of Escherichia coli, which catalyzes translation termination at UGA and UAA codons. The gene, identified by sequencing, is located at the 62-min region of the E. coli chromosome. The prfB gene is followed by an open reading frame encoding a 57,603-Da protein. This downstream open reading frame was identified as herC, a gene defined by a suppressor mutation that restores replication of a ColE1 plasmid mutant. RNA blot hybridization and S1 nuclease protection analyses of in vivo transcripts showed that prfB and herC are cotranscribed into a 2800-base transcript in the counterclockwise direction with respect to the E. coli genetic map. Thus, we refer to the two genes as the prfB-herC operon. Data are presented that suggest that supK, a mutation in Salmonella typhimurium that suppresses UGA termination, is the structural gene for Salmonella release factor 2. Translation control within the prfB-herC operon and the relationship of these genes to a tRNA methyltransferase are discussed.
- Publication:
-
Proceedings of the National Academy of Science
- Pub Date:
- August 1988
- DOI:
- 10.1073/pnas.85.15.5620
- Bibcode:
- 1988PNAS...85.5620K