碱基堆积和碱基配对对螺旋稳定性的贡献：CCGG、CCGGp、CCGGAp、ACCGGp、CCGGUp和ACCGGUp形成双螺旋的热力学

Base-stacking and base-pairing contributions to helix stability: thermodynamics of double-helix formation with CCGG, CCGGp, CCGGAp, ACCGGp, CCGGUp, and ACCGGUp.

作者信息

Petersheim M, Turner D H

出版信息

Biochemistry. 1983 Jan 18;22(2):256-63. doi: 10.1021/bi00271a004.

Abstract

The thermodynamics of double-helix formation in 1 M NaCl have been measured spectrophotometrically for CCGG, CCGGp, CCGGAp, ACCGGp, CCGGUp, and ACCGGUp. The results indicate additional double-helical stability is conferred by the terminal unpaired bases. The 3' A stabilizes the double helix more than the 5' A or the 3' U. The increased stability is due to a more favorable enthalpy change for double-helix formation. Comparison of the thermodynamics for CCGG, ACCGGp, CCGGUp, and ACCGGUp indicates stacking interactions are somewhat more important than pairing interactions in determining the stability of the terminal AU base pairs in ACCGGUp.

摘要

已通过分光光度法测量了在1 M氯化钠中CCGG、CCGGp、CCGGAp、ACCGGp、CCGGUp和ACCGGUp形成双螺旋的热力学。结果表明，末端未配对碱基赋予了额外的双螺旋稳定性。3'端的A比5'端的A或3'端的U更能稳定双螺旋。稳定性的增加归因于双螺旋形成时更有利的焓变。对CCGG、ACCGGp、CCGGUp和ACCGGUp的热力学比较表明，在确定ACCGGUp中末端AU碱基对的稳定性时，堆积相互作用比配对相互作用更为重要。