Inhibition by L-aspartol adenylate of a nondiscriminating aspartyl-tRNA synthetase reveals differences between the interactions of its active site with tRNA(Asp) and tRNA(Asn).
J Enzyme Inhib Med Chem
; 22(1): 77-82, 2007 Feb.
Article
en En
| MEDLINE
| ID: mdl-17373551
Asparaginyl-tRNA formation in Pseudomonas aeruginosa PAO1 involves a nondiscriminating aspartyl-tRNA synthetase (ND-AspRS) which forms Asp-tRNA(Asp) and Asp-tRNA(Asn), and a tRNA-dependent amidotransferase which transamidates the latter into Asn-tRNA(Asn). We report here that the inhibition of this ND-AspRS by L-aspartol adenylate (Asp-ol-AMP), a stable analog of the natural reaction intermediate L-aspartyl adenylate, is biphasic because the aspartylation of the two tRNA substrates of ND-AspRS, tRNA(Asp) and tRNA(Asn), are inhibited with different Ki values (41 microM and 215 microM, respectively). These results reveal that the two tRNA substrates of ND-AspRS interact differently with its active site. Yeast tRNA(Asp) transcripts with some identity elements replaced by those of tRNA(Asn) have their aspartylation inhibited with Ki values different from that for the wild-type transcript. Therefore, aminoacyl adenylate analogs, which are competitive inhibitors of their cognate aminoacyl-tRNA synthetase, can be used to probe rapidly the role of various structural elements in positioning the tRNA acceptor end in the active site.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Aspartato-ARNt Ligasa
/
ARN de Transferencia de Asparagina
/
ARN de Transferencia de Aspártico
/
Adenosina Monofosfato
/
Ácido Aspártico
/
Inhibidores Enzimáticos
Idioma:
En
Revista:
J Enzyme Inhib Med Chem
Asunto de la revista:
BIOQUIMICA
/
QUIMICA
Año:
2007
Tipo del documento:
Article
País de afiliación:
Canadá
Pais de publicación:
Reino Unido