Combining electron microscopy and X-ray crystallography data to study the structure of F-actin and its implications for thin-filament regulation in muscle.

The convergence of structures, all determined by independent global searches and subsequent refinement on different electron microscopy data sets, with the X-ray fiber diffraction results strongly suggests that we now have the approximately correct structure for F-actin. This consensus structure will now provide a reliable, well-defined platform upon which to study the structure and function of proteins bound to actin. Among these are capping proteins, such as severin and gelsolin, contractile proteins, such as myosin and its subfragments, and proteins involved in regulation, such as troponin and tropomyosin.