Wu M, McDowell J A, Turner D H
Department of Chemistry, University of Rochester, New York 14627-0216.
Biochemistry. 1995 Mar 14;34(10):3204-11. doi: 10.1021/bi00010a009.
The stabilities and structures of a series of RNA octamers containing symmetric tandem mismatches were studied by UV melting and imino proton NMR. The free energy increments for tandem mismatch formation are found to depend upon both mismatch sequence and adjacent base pairs. The observed sequence dependence of tandem mismatch stability is UGGU > GUUG > GAAG > or = AGGA > UUUU > CAAC > or = CUUC approximately UCCU approximately CCCC approximately ACCA approximately AAAA, and the closing base pair dependence is 5'G3'C > 5'C3'G > 5'U3'A approximately 5'A3'U. These results differ from expectations based on models used in RNA folding algorithms and from the sequence dependence observed for folding of RNA hairpins. Imino proton NMR results indicate the sequence dependence is partially due to hydrogen bonding within mismatches.
通过紫外熔解和亚氨基质子核磁共振研究了一系列含有对称串联错配的RNA八聚体的稳定性和结构。发现串联错配形成的自由能增量取决于错配序列和相邻碱基对。观察到的串联错配稳定性的序列依赖性为UGGU > GUUG > GAAG ≥ AGGA > UUUU > CAAC ≥ CUUC ≈ UCCU ≈ CCCC ≈ ACCA ≈ AAAA，而封闭碱基对的依赖性为5'G3'C > 5'C3'G > 5'U3'A ≈ 5'A3'U。这些结果不同于基于RNA折叠算法中使用的模型的预期，也不同于RNA发夹折叠所观察到的序列依赖性。亚氨基质子核磁共振结果表明，序列依赖性部分归因于错配内的氢键作用。
