THERMODYNAMIC AND ACTIVATION PARAMETERS FOR BINDING OF A PYRENE-LABELED SUBSTRATE BY THE TETRAHYMENA RIBOZYME - DOCKING IS NOT DIFFUSION-CONTROLLED AND IS DRIVEN BY A FAVORABLE ENTROPY

被引：53

作者：

LI, Y ^{[1
]}

BEVILACQUA, PC ^{[1
]}

MATHEWS, D ^{[1
]}

TURNER, DH ^{[1
]}

机构：

[1] UNIV ROCHESTER, DEPT CHEM, ROCHESTER, NY 14627 USA

来源：

BIOCHEMISTRY | 1995年 / 34卷 / 44期

关键词：

D O I：

10.1021/bi00044a016

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Association and dissociation rates for the pyrene-(pyr)-labeled oligoribonucleotide substrate pyrCUCU binding to the L-21 ScaI group I ribozyme are reported as a function of temperature. Combined with thermodynamic parameters for binding of pyrCUCU to rGGAGAA, the results allow calculation of the activation and thermodynamic parameters for docking of pyrCUCU into the catalytic core of the ribozyme. The activation enthalpy for docking is 22 kcal/mol, much larger than the similar to 4 kcal/mol expected for a diffusion-controlled process. Thus, docking is not diffusion-controlled The activation and equilibrium entropies for docking are favorable at 21 and 37 eu, respectively. The results suggest the rate-limiting step and the driving force for docking may involve desolvation of RNA functional groups or of Mg2+ ions.

引用

页码：14394 / 14399

页数：6

共 59 条

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