RuvA protein bound to DNA - side view

The E. coli RuvA protein binding to two strands of DNA in the process of homologous recombination (a structure known as a Holliday junction). The protein is coloured to show the electrostatic charge (blue=positve, white=neutral and orange=negative). The backbones of the individual strands of the DNA have been coloured blue, red, yellow and green.