[The effect of modification of nucleotide-37 on the interaction of aminoacyl-tRNA with the A-site of the 70S ribosome].
To estimate the effect of modified nucleotide-37, the interaction of two yeast aminoacyl-tRNAs (Phe-tRNAK+YPhe and Phe-tRNAK-YPhe) with the A site of complex [70S.poly(U).deacylated tRNA(Phe) in the P site] was assayed at 0-20 degrees C. As comparisons with native Phe-tRNAK+YPhe showed, removal of the Y base decreased the association constant of Phe-tRNAK-YPhe and the complex by an order of magnitude at any temperature, and increased the enthalpy of their interaction by 23 kJ/mol. When the Y base was present in the anticodon loop of deacylated tRNA(Phe) bound to the P site of the 70S ribosome, twice higher affinity for the A site was observed for Phe-tRNAK-YPhe but not for Phe-tRNAK+YPhe. Thus, the modified nucleotide 3' of the Phe-tRNA(Phe) anticodon stabilized the codon-anticodon interaction both in the A and in the P sites of the 70S ribosome.
Soboleva
N G
NG
Konstantinov Institute of Nuclear Physics, Russian Academy of Sciences, Gatchina, Leningrad Oblast, 188300 Russia.
Makhno
V I
VI
Konevega
A L
AL
Semenkov
Iu P
IuP
Katunin
V I
VI
D000926:Anticodon; D001665:Binding Sites; D004926:Escherichia coli / Q000235:genetics; D016297:Mutagenesis, Site-Directed; D009711:Nucleotides / Q000235:genetics; D012346:RNA, Transfer, Amino Acyl / Q000235:genetics / Q000378:metabolism*; D012360:RNA, Transfer, Phe / Q000235:genetics / Q000378:metabolism; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism*
D000926:Anticodon; D009711:Nucleotides; D012346:RNA, Transfer, Amino Acyl; D012360:RNA, Transfer, Phe