Binding to four‐way junction DNA: a common property of architectural proteins?

Proteins that can be shown to strongly bind in vitro to the four‐way (Holliday) junction DNA include not only the obvious candidates such as enzymes involved in recombination, but also a remarkably diverse group of seemingly unrelated proteins. These include the HMG1 box proteins, members of the HMGI‐Y family, winged helix proteins (including linker histones), the SWI/SNF complex, and some totally unrelated prokaryotic proteins. What these proteins seem to share is a propensity to bind to bent DNA, to bend DNA upon binding, and/or to preferentially interact with DNA crossings. Thus, they appear to be, in the main, architectural proteins, although some (like the SWI/SNF complex) have very specific functional roles as well. Perhaps because they bind to or promote the formation of particular DNA structures, the four‐way junction binding proteins are frequently interchangeable in cellular function. Furthermore, since a given kind of structure can be recognized by many different protein motifs, it is not surprising that apparently unrelated proteins can fall into such a single functional class.—Zlatanova, J., van Holde, K. Binding to four‐way junction DNA: a common property of architectural proteins? FASEB J. 12, 421–431 (1998)