Vorob'ev Iu N, Knorre D G
Mol Biol (Mosk). 1979 Jan-Feb;13(1):140-51.
The conformation analysis of tRNA acceptor fragment XCCA (X=A) was performed. The ribose conformation was taken rigid C(3')-endo. The optimum conformation was found for the ACCA fragment. It was shown that the omega, omega'-angle of the terminal adenine in any crystal modification of the yeast tRNAFen is not optimal. The conformation mobility of the 3'-end ACCA fragment was calculated in the vicinity of optimum conformation. Redundant energy required for keeping the correct 3'-terminal tRNA orientation about the enzyme catalytic centre during any small orientation distortions of the non-universal X-nucleotide relative to the enzyme was estimated. The distortions may occur when non-gomologous tRNA interact with aminoacyl-tRNA-synthetase. It was found that redundant energy for 3' displacement is very anisotropic and some small X-nucleotide reorientation may decrease the catalitic velocity of aminoacylation u0(4)--10(5) times.
对tRNA受体片段XCCA（X = A）进行了构象分析。核糖构象采用刚性的C(3')-内型。找到了ACCA片段的最佳构象。结果表明，酵母tRNAFen任何晶体变体中末端腺嘌呤的ω、ω'-角都不是最佳的。计算了3'-末端ACCA片段在最佳构象附近的构象流动性。估计了在非通用X核苷酸相对于酶发生任何小的方向扭曲时，保持tRNA 3'-末端关于酶催化中心正确取向所需的多余能量。当非同源tRNA与氨酰-tRNA合成酶相互作用时可能会发生这种扭曲。结果发现，3'位移的多余能量非常各向异性，一些小的X核苷酸重新取向可能会使氨酰化催化速度降低u0(4)--10(5)倍。
