The kinetics of the interaction between the actin‐binding domain of α‐actinin and F‐actin

FEBS Letters

Kuhlman, Philip A.¹  Ellis, Jacqueline¹  Critchley, David R.¹  Bagshaw, Clive R.¹ 

[1] Department of Biochemistry, University of Leicester, University Road, Leicester, LE1 7RH, UK

关键词: α-Actinin;    Stopped-flow;    Actin-bundling;    Actin;    Light scattering;    Tryptophan fluorescence;   

DOI  :  10.1016/0014-5793(94)80434-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Measurement of the binding equilibrium for the interaction of α-actinin with F-actin is complicated by secondary reactions involving cross-linking and/or bundling of the actin filaments. To quantitate the initial binding event, we studied the interaction of the bacterially expressed actin-binding domain (ABD) of chick smooth muscle α-actinin with F-actin. Stopped-flow measurements revealed a quench in protein fluorescence and an enhancement in light scattering when ABD binds to F-actin yielding second order rate constants for association of 2 × 10⁵, 1.8 × 10⁶ and 4 × 10⁶ M⁻¹ · s⁻¹ at 5°C, 15°C and 25°C, respectively. At the latter two temperatures the dissociation rate constants were 1.5 and 9.6 s⁻¹, giving equilibrium constants of 0.83 and 2.4 μM, respectively. Optical changes on mixing intact α-actinin with F-actin were dominated by secondary bundling events.

【 授权许可】

Unknown