Identification of transfer RNA suppressors in Escherichia coli. I. Amber suppressor su+2, an anticodon mutant of tRNA2Gln. |
| |
Authors: | H Inokuchi F Yamao H Sakano H Ozeki |
| |
Affiliation: | Department of Biophysics, Faculty of Science Kyoto University, Kyoto 606, Japan |
| |
Abstract: | In order to isolate the gene for amber suppressor su+2 (SupE) in Escherichia coli, a non-defective su+2-transducing phage lambda was isolated in three steps: first, deletion derivatives of F′su+2 gal (λ) were selected, linking su+2 to the right-hand prophage attachment site, attλPB′; second, these F′-factors were relysogenized by λ and defective transducing phages, λdsu+2, were produced by induction; and third, non-defective λpsu+2 transducing phages were produced by recombination of λdsu+2 isolates with λ. Upon infection by λpsu+2, the production of transferRNAs accepting glutamine and methionine was markedly stimulated. Fingerprint analysis of these tRNAs revealed that they consisted of normal tRNA2Gln, mutant tRNA2Gln and tRNAmMet. The mutant tRNA2Gln carried a singlebase alteration from G to A at the 3′-end of the anticodon. The production of tRNA1Gln was not stimulated by the infection of λpsu+2. We conclude that the wild-type allele of su+2 (SupE) is the structural gene for tRNA2Gln, and the su+2 amber suppressor was derived by a single base mutation, changing the anticodon from CUG to CUA, in one of the multi-copy genes for tRNA2Gln. The fact that λpsu+2 also induces the production of tRNAmMet suggests that this tRNA is encoded in the same chromosomal region of E. coli as is tRNA2Gln. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|