Open AccessMutual conformational changes of tryptophanyl‐tRNA synthetase and tRNA Trp in the course of their specific interaction
Author(s) -
BERESTEN Sergey,
SCHEINKER Vladimir,
FAVOROVA Olga,
KISSELEV Lev
Publication year - 1983
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1983.tb07777.x
Subject(s) - transfer rna , aminoacylation , biochemistry , proteolysis , biology , rnase p , enzyme , cytidine , rna , cleavage (geology) , yeast , aminoacyl trna synthetase , nucleotide , paleontology , fracture (geology) , gene
tRNA Trp (beef, yeast) is capable of accelerating limited tryptic hydrolysis of the N‐terminal part in the polypeptide chains of dimeric beef pancreas tryptophanyl‐tRNA synthetase; it can also eliminate the protective effect of tryptophanyl adenylate on the enzyme proteolysis. The effect of tRNA on the proteolysis is manifested even when the 3′‐CCA terminus is removed. It has been concluded that the conformation of the synthetase changes when it forms a complex with tRNA Trp . Yeast tRNA Trp lacking the 3′‐half of the acceptor stem can still interact with the synthetase and, to certain extent, induces changes in the conformation of the latter. The susceptibility of single‐stranded and double‐stranded regions of tRNA Trp to cleavage with endonucleases has been studied, and the results are indicative of the fact that, regardless of considerable differences in the nucleotide sequence of yeast and beef tRNA Trp , their three‐dimensional structures are similar. This fact is consistent with the finding that parameters for the interaction of these tRNAs Trp with beef tryptophanyl‐tRNA synthetase are rather close. The three‐dimensional structure of tRNA Trp is altered when the enzyme forms a complex with it, as seen from (a) a change in the circular dichroic spectrum and (b) an elevated susceptibility of the anticodon and, apparently, acceptor stems to cleavage with nuclease. The conversion of exposed cytidine residues in tRNA Trp into uridine residues results in a loss of the acceptor activity; the capability to accelerate limited tryptic hydrolysis of tryptophanyl‐tRNA synthetase is also lost although the enzyme‐substrate complex, as seen from circular dichroic spectra, can still be formed. The conversion of cytosine in the anticodon stem into uracil modifies the conformation of the anticodon stem. The anticodon arm (including the anticodon) and the acceptor stem play an essential role in the interaction between tRNA Trp and tryptophanyl‐tRNA synthetase.