Asparagine‐135 of elongation factor Tu is a crucial residue for the folding of the guanine nucleotide binding pocket

FEBS Letters

Parmeggiani, Andrea²  Bârzu, Octavian³  Sarfati, Robert¹  Weijland, Albert² 

[1] Unité 2 Chimie Organique, U.R.A. 487 du C.N.R.S., Institut Pasteur, F-72724 Paris-Cedex, France;SDI n° 61840 du CNRS, Laboratoire de Biochimie, Ecole Polytechnique, F-91128 Palaiseau Cedex, France;Unité de Biochimie des Régulations Cellulaires, U.R.A. 1129 du C.N.R.S., Institut Pasteur, F-72724 Paris-Cedex, France

关键词: EF-Tu;    Folding of GTP-binding pocket;    Base recognition;    isoGTP;   

DOI  :  10.1016/0014-5793(93)80899-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

This work studies the structure-function relationships of Asn¹³⁵, a residue situated in the GTP binding pocket of elongation factor Tu (EF-Tu). For this purpose we constructed EF-TuN135D/D138N and assayed its reactivity towards various purine nucleotides. We found that EF-TuN135D/D138N had no functional effect with GTP, ATP, XTP and isoGTP. The lack of a productive interaction with isoGTP shows that the Asn¹³⁵ side-chain does not recognize the exocyclic keto group of the guanine base. However, EF-TuN 135D/D 138N, whose native conformation is stabilized by either elongation factor Ts or kirromycin, was able to support the enzymatic binding of aa-tRNA to the ribosome in the absence of any nucleotide, when in complex with the antibiotic. Taken together, these results show that Asn¹³⁵ is important for the correct folding of the nucleotide binding site and that EF-Tu·kirromycin can mediate the binding of aa-tRNA to the mRNA-programmed ribosomes independently of the native conformation of this site.

【 授权许可】

Unknown