Toward a general chemical method for rapidly mapping multi-protein complexes.

Ru(II)(bpy2)32+Cl2, ammonium persulfate, and visible light irradiation has been shown to rapidly and efficiently cross-link several interacting proteins. However, this methodology has not yet been used to map the architecture of large multi-protein complexes. In this study, this chemistry is applied to the crystallographically characterized yeast proteasome. The data obtained demonstrate both the method's increased generality and fidelity in comparison to traditional bifunctional cross-linking reagents, while also highlighting the future need for developing better analytical techniques to separate cross-linked products.