STRUCTURAL SIMILARITIES BETWEEN ESCHERICHIA-COLI RUVA PROTEIN AND OTHER DNA-BINDING PROTEINS AND A MUTATIONAL ANALYSIS OF ITS BINDING TO THE HOLLIDAY JUNCTION

Comparison of the structure of Escherichia coli RuvA with other protei ns in the Protein Data Bank gives insights into the probable modes of association of RuvA with the Hollday junction during homologous recomb ination. All three domains of the RuvA protein possess striking struct ural similarities to other DNA-binding proteins. Additionally, the sec ond domain of RuvA contains two copies of the helix-hairpin-helix (HhH ) structural motif, which has been implicated in non-sequence-specific DNA binding. The two copies of the motif are related by approximate 2 -fold symmetry and may form a bidentate DNA-binding module. The result s described provide support for the organization of the arms of the DN A in our RuvA/Holliday junction complex model and support the involvem ent of the HhH motifs in DNA binding. (C) 1998 Academic Press Limited.