Functional mutants of phenylalanine transfer RNA from Escherichia coli.
AUTOR(ES)
Vacher, J
RESUMO
The gene pheV from Escherichia coli, coding for tRNAPhe and carried on a plasmid, has been mutagenised with hydroxylamine. Mutants in the structural gene have been identified using two criteria: (i) de-attenuation of beta-galactosidase expression, while under the control of the attenuator region of the pheS,T operon by means of an operon fusion; (ii) loss of ability to complement thermosensitivity of a mutant Phe-tRNA synthetase. Mutants showing de-attenuation were sequenced and two nucleotide changes identified: G44----A44 (found five times) and m7G46----A46 (found once). Sequencing of mutants that lost complementation identified two further tRNA mutants, C2---U2 and G15----A15; the mutant m7G46----A46 was also re-isolated by this criterion. Three of the mutants involve bases implicated in tertiary rather than secondary structure hydrogen bonding. One hypothesis for the mechanism of de-attenuation is that mutant tRNAPhe molecules compete with the wild-type tRNAPhe on the ribosome but are inefficient at some step in the elongation process.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=554214Documentos Relacionados
- Increased isoleucine acceptance by sulfur-deficient transfer RNA from Escherichia coli.
- RNA polymerase mutants of Escherichia coli. I. Mutants resistant to streptovaricin.
- Growth rate dependence of transfer RNA abundance in Escherichia coli.
- Transfer-Defective Mutants of Sex Factors in ESCHERICHIA COLI. I. Defective Mutants and Complementation Analysis
- Topology of the phenylalanine-specific permease of Escherichia coli.
