Actomyosin modulation by peroxynitrite

Tiago, Teresa; Silva, D.; Santos, Ana; Aureliano, M.; Gutiérrez-Merino, Carlos

http://hdl.handle.net/10400.1/1310

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Authors

Gutiérrez-Merino, Carlos

Abstract(s)

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.