Actomyosin modulation by peroxynitrite

• Author(s): Tiago, Teresa ; Silva, D. ; Santos, A. ; Aureliano, M. ; Gutiérrez-Merino, Carlos
• Date: 2007
• Persistent ID: http://hdl.handle.net/10400.1/1310
• Origin: Sapientia - Universidade do Algarve
• Subject(s): Actomyosin; Peroxynitrite
• Document Type: Conference Object
• Language: English

Description

In the present work we address the oxidative modifications accounting for the structural and functional impairment of the actomyosin complex under the oxidative stress mediated by peroxynitrite (ONOO-). Experiments on purified myosin and actin have shown that submicromolar ONOO- concentrations produce strong inhibition of the F-actin stimulated myosin ATPase activity. The peroxynitrite-induced actomyosin impairment correlated with structural modifications that decrease the thermal stability of both actin and myosin leading to partially unfolded states. The results suggest a major role for the highly reactive cysteines on actin and on myosin and also for some critical methionines on G-actin. 3-nitrotyrosine does not contribute significantly to the observed functional alterations.