The C‐A mismatch base pair and the single‐strand terminus in the E. coli initiator tRNAfMet acceptor stem adopt unusual conformations

FEBS Letters

Limmer, Stefan¹  Schübel, Harald¹  Zuleeg, Tilman¹  Vogtherr, Martin¹ 

[1] Laboratorium für Biochemie, Universität Bayreuth, Universitätsstraße 30, D-95440 Bayreuth, Germany

关键词: Initiator tRNA;    Acceptor stem;    C-A base pair;    tRNA identity;    Nuclear magnetic resonance;   

DOI  :  10.1016/S0014-5793(00)01459-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Acceptor stem variants of tRNA^fMet (Escherichia coli) have been characterized by nuclear magnetic resonance. The wild type contains a C1-A72 mismatch pair which is crucial for its biological function. For comparison, the mismatch was replaced by regular pairs U1-A72 and C1-G72. Further variants contain an altered discriminator base, G73, or a G1-C72/U73 combination. The stems of variants U1-A72/A73 and C1-G72/A73 have A-RNA geometry, which extends essentially to the single-strand terminus. C1-A72/G73 variant and wild type are structurally almost identical. C1 and A72 adopt peculiar conformations with C1 being largely destacked with respect to G2, while A73 stacks upon C1. The unique arrangement of the mismatch causes a distinctly different orientation of the single-strand terminus compared to variants with regular 1–72 base pairs, and to formyltransferase-complexed tRNA^fMet.

【 授权许可】

Unknown