Allosteric inhibition of myosin by phenamacril: a synergistic mechanism revealed by computational and experimental approaches

BackgroundMyosin plays a crucial role in cellular processes, while its dysfunction can lead to organismal malfunction. Phenamacril (PHA), a highly species-specific and non-competitive inhibitor of myosin I (FgMyoI) from Fusarium graminearum, has been identified as an effective fungicide for controlling plant diseases caused by partial Fusarium pathogens, such as wheat scab and rice bakanae. However, the molecular basis of its action is still unclear. ResultsThis study used multiple computational approaches first to elucidate the allosteric inhibition mechanism of FgMyoI by PHA at the atomistic level. The results indicated the increase of adenosine triphosphate (ATP) binding affinity upon PHA binding, which might impede the release of hydrolysis products. Furthermore, simulations revealed a broadened outer cleft and a significantly more flexible interface for actin binding, accompanied by a decrease in signaling transduction from the catalytic center to the actin-binding interface. These various effects might work together to disrupt the actomyosin cycle and hinder the ability of motor to generate force. Our experimental results further confirmed that PHA reduces the enzymatic activity of myosin and its binding with actin. ConclusionTherefore, our findings demonstrated that PHA might suppress the function of myosin through a synergistic mechanism, providing new insights into myosin allostery and offering new avenues for drug/fungicide discovery targeting myosin. & COPY; 2023 Society of Chemical Industry.

Automated summary

This study used multiple computational approaches to elucidate the allosteric inhibition mechanism of Phenamacril (PHA) on Myosin I (FgMyoI) from Fusarium graminearum. The results showed that PHA binding increased the ATP binding affinity, which hindered the release of hydrolysis products. Simulations also revealed changes in the actin-binding interface and signaling transduction, disrupting the actomyosin cycle and reducing motor force generation. Experimental results confirmed that PHA reduced the enzymatic activity of myosin and its binding with actin. Overall, this study provides new insights into myosin allostery and offers opportunities for drug/fungicide discovery targeting myosin.