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NMR analyses on the molecular mechanism of the conformational rigidity of 2‐thioribothymidine, a modified nucleoside in extreme thermophile tRNAs
Author(s) -
Yamamoto Yuriko,
Yokoyama Shigeyuki,
Miyazawa Tatsuo,
Watanabe Kimitsuna,
Higuchi Shigesada
Publication year - 1983
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(83)81123-5
Subject(s) - stereochemistry , steric effects , thermophile , chemistry , nucleoside , thermostability , moiety , biochemistry , enzyme
1 H‐NMR analyses have been made on the conformations of 2‐thioribothymidine (s 2 T), 2‐thiodeoxyribothymidine (s 2 dT), as well as ribothymidine (T) and deoxyribothymidine (dT). s 2 T and s 2 dT exclusively take the anti form rather than the syn form. The C3'‐endo‐gg form of the sugar moiety is remarkably stabilized on modification of T to s 2 T, but not on modification of dT to s 2 dT. The steric effects of the 2‐thiocarbonyl group and the 2'‐hydroxyl group cause the rigidity of the C3'‐endo‐gg form of s 2 T. Such rigidity of s 2 T probably contributes to the thermostability of 2‐thiopyrimidine polyribonucleotides and extreme thermophile tRNAs.