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Conformational changes of aminoacyl‐tRNA and unchanged tRNA upon complex formation with polypeptide chain elongation factor Tu
Author(s) -
Haruki Mitsuru,
Matsumoto Rieko,
Hara-Yokoyama Miki,
Miyazawa Tatsuo,
Yokoyama Shigeyuki
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)81414-j
Subject(s) - thermus thermophilus , ef tu , gtp' , aminoacyl trna , transfer rna , ternary complex , guanosine triphosphate , chemistry , stereochemistry , circular dichroism , conformational change , polypeptide chain , crystallography , biophysics , biochemistry , biology , rna , escherichia coli , enzyme , gene
The conformation change of Thermus thermophilus tRNA Ile 1 upon complex formation with T. thermophilus elongation factor Tu (EF‐Tu) was studied by analysis of the circular dichroism (CD) bands at 315 nm (due to the 2‐thioribothymidine residue in the T‐loop) and at 295 nm (due to the core structure of tRNA). Formation of the ternary complex of isoleucyl‐tRNA Ile 1 and EF‐Tu·GTP increased the intensities of these CD bands, indicating stabilization of the association between the T‐loop and the D‐loop and also a significant conformation change of the core region. Upon complex formation of EF‐Tu·GTP and unchanged tRNA, however, the conformation of the core region is not changed, while the association of the two loops is still stabilized. On the other hand, the binding with EF‐Tu·GDP does not appreciably affect the conformation of isoleucyl‐tRNA or unchanged tRNA. These indicate the importance of the γ‐phosphate group of GTP and the aminoacyl group in the formation of the active complex of aminoacyl‐tRNA and EF‐Tu·GTP.