Interaction of myosin subfragment 1 with F-actin studied by differential scanning calorimetry

• Published in: Biochemistry and molecular biology international Vol. 40; no. 4; p. 653
• Main Authors: Nikolaeva, O P, Orlov, V N, Dedova, I V, Drachev, V A, Levitsky, D I
• Format: Journal Article
• Language: English
• Published: England 01.11.1996
• Subjects: Actins - metabolism; Animals; Calorimetry, Differential Scanning; Myosin Subfragments - metabolism; Protein Conformation; Rabbits
• ISSN: 1039-9712
• DOI: 10.1080/15216549600201253

The thermal unfolding of the myosin subfragment 1 (S1) and of filamentous actin (F-actin) in their strong complex obtained in the presence of ADP was studied by differential scanning calorimetry (DSC). It is shown that in the acto-S1 complexes S1 and F-actin melt separately, and thermal transitions of each protein can be easily followed. Interaction of S1 with F-actin significantly increases S1 thermal stability and also affects the thermal stability of F-actin. Although S1 unfolds at much lower temperature than F-actin, the molecules of S1 remain bound to F-actin even after full denaturation. Under these conditions S1 may induce cross-linking between actin filaments. It is concluded that DSC studies on the acto-S1 complexes offer a new and promising approach to investigate the structural changes which occur in the myosin head and in F-actin due to their interaction.