Changes in the thermal unfolding of p‐phenylenedimaleimide‐modified myosin subfragment 1 induced by its ‘weak’ binding to F‐actin

FEBS Letters

Drachev, Vladimir A.¹  Ponomarev, Michael A.²  Orlov, Victor N.¹  Nikolaeva, Olga P.¹  Kaspieva, Olga V.¹  Levitsky, Dmitrii I.¹ 

[1] A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russia;A.N. Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow 117071, Russia

关键词: Actin–myosin interaction;    Myosin subfragment 1;    Thermal unfolding;    Differential scanning calorimetry;    S1;    myosin subfragment 1;    pPDM;    N;    N′-p-phenylenedimaleimide;    DSC;    differential scanning calorimetry;   

DOI  :  10.1016/S0014-5793(01)02093-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Differential scanning calorimetry (DSC) was used to analyze the thermal unfolding of myosin subfragment 1 (S1) with the SH1 (Cys-707) and SH2 (Cys-697) groups cross-linked by N,N′-p-phenylenedimaleimide (pPDM-S1). It has been shown that F-actin affects the thermal unfolding of pPDM-S1 only at very low ionic strength, when some part of pPDM-S1 binds weakly to F-actin, but not at higher ionic strength (200 mM KCl). The weak binding of pPDM-S1 to F-actin shifted the thermal transition of pPDM-S1 by about 5°C to a higher temperature. This actin-induced increase in thermal stability of pPDM-S1 was similar to that observed with ‘strong’ binding of unmodified S1 to F-actin. Our results show that actin-induced structural changes revealed by DSC in the myosin head occur not only upon strong binding but also on weak binding of the head to F-actin, thus suggesting that these changes may occur before the power-stroke and play an important role in the motor function of the head.

【 授权许可】

Unknown