The heterotrimeric Thermus thermophilus Asp‐tRNAAsn amidotransferase can also generate Gln‐tRNAGln

FEBS Letters

Jacobi, Carsten²  Becker, Hubert D.¹  Raczniak, Gregory¹  Kern, Daniel³  Roy, Hervé³  Min, Bokkee¹  Pelaschier, Joanne¹  Söll, Dieter¹  Klein, Sylvain³ 

[1] Department of Molecular Biophysics and Biochemistry, Yale University, P.O. Box 208114, 266 Whitney Avenue, New Haven, CT 06520-8114, USA;Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Grisebachstrasse 8, D-37077 Göttingen, Germany;Institut de Biologie Moléculaire et Cellulaire du C.N.R.S., 15 Rue René Descartes, F-67084 Strasbourg Cedex, France

关键词: Aminoacyl-tRNA;    tRNA-dependent amidation;    Thermus thermophilus;    tRNA specificity;   

DOI  :  10.1016/S0014-5793(00)01697-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Thermus thermophilus strain HB8 is known to have a heterodimeric aspartyl-tRNA^Asn amidotransferase (Asp-AdT) capable of forming Asn-tRNA^Asn [Becker, H.D. and Kern, D. (1998) Proc. Natl. Acad. Sci. USA 95, 12832–12837]. Here we show that, like other bacteria, T. thermophilus possesses the canonical set of amidotransferase (AdT) genes (gatA, gatB and gatC). We cloned and sequenced these genes, and constructed an artificial operon for overexpression in Escherichia coli of the thermophilic holoenzyme. The overproduced T. thermophilus AdT can generate Gln-tRNA^Gln as well as Asn-tRNA^Asn. Thus, the T. thermophilus tRNA-dependent AdT is a dual-specific Asp/Glu-AdT resembling other bacterial AdTs. In addition, we observed that removal of the 44 carboxy-terminal amino acids of the GatA subunit only inhibits the Asp-AdT activity, leaving the Glu-AdT activity of the mutant AdT unaltered; this shows that Asp-AdT and Glu-AdT activities can be mechanistically separated.

【 授权许可】

Unknown