The structure of S1-decorated actin filaments calculated from x-ray diffraction data with phases derived from electron micrographs.

A composite data set in Fourier space has been produced from electron micrographs of negatively stained decorated actin and X-ray fibre diffraction patterns of glycerinated insect muscle "decorated" with rabbit myosin cross-bridges. It is shown that a simple model of actin and myosin may be adjusted to fit this data. The model conforms to the Taylor-Amos geometry for the acto-myosin interaction in accordance with the idea that the cross-bridge binds to two neighbouring actin monomers on different strands.