A Discriminator Base in tDNATrp

A Discriminator Base in tDNA^Trp

CHEN Li,JIN You-Xin^** and WANG De-Bao
( State Key Laboratory of Molecular Biology,Shanghai Institute of
Biochemistry,the Chinese Academy of Sciences,Shanghai 200031,China
)

Abstract　The discriminator base G73 was
one of the major identity elements of tRNA^Trp. Aminoacylation assay
and CD spectrum of tDNA^Trp-NCCrA demonstrated that under the same
pH,the change of discriminator base affected tRNA conformation at the 3′
terminus；while
tDNA^Trp with the same discriminator base exhibited different
conformation and aminoacylation activity under various pH conditions. Our
results showed that it was the conformation of tRNA,but not the base
itself,that determined the accurate recognition between tRNA and its cognate
synthetase.
Key Words　tDNA^Trp；discriminator base；CD spectrum；tryptophanyl-tRNA synthetase

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