Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, United States.
Biochemistry. 2011 Mar 8;50(9):1429-31. doi: 10.1021/bi102057m. Epub 2011 Feb 2.
The RNA recognition motif (RRM) is a prevalent class of RNA binding domains. Although a number of RRM/RNA structures have been determined, thermodynamic analyses are relatively uncommon. Here, we use isothermal titration calorimetry to characterize single-stranded (ss)RNA binding by four representative RRM-containing proteins: (i) U2AF(65), (ii) SXL, (iii) TIA-1, and (iv) PAB. In all cases, ssRNA binding is accompanied by remarkably large favorable enthalpy changes (-30 to -60 kcal mol(-1)) and unfavorable entropy changes. Alterations of key RRM residues and binding sites indicate that under the nearly physiological conditions of these studies, large thermodynamic changes represent a signature of specific ssRNA recognition by RRMs.
RNA 识别基序（RRM）是一类普遍存在的 RNA 结合结构域。尽管已经确定了许多 RRM/RNA 结构，但热力学分析相对较少。在这里，我们使用等温滴定量热法来表征四个代表性的含有 RRM 的蛋白质与单链（ss）RNA 的结合：（i）U2AF（65），（ii）SXL，（iii）TIA-1，和（iv）PAB。在所有情况下，ssRNA 结合伴随着非常大的有利焓变（-30 至-60 kcal mol（-1））和不利的熵变。关键 RRM 残基和结合位点的改变表明，在这些研究的几乎生理条件下，大的热力学变化代表了 RRMs 特异性识别 ssRNA 的特征。
