Interaction of cisplatin and analogues with a Met-rich protein site

Abstract

The chaperone protein CopC from Pseudomonas syringae features high-affinity binding sites (K D ~ 10-13 M) for both CuI (Met-rich) and CuII (His-rich). When presented with these sites in the apoprotein, electrospray ionisation mass spectrometry confirmed that cis-Pt(NH3)2Cl2 (cisplatin) and the fragments [PtIIL]2+ (L is 1,2-diaminoethane, 2,2′-bipyridine) occupied the CuI site specifically in the 1:1 Pt-CopC adducts (purified by cation-exchange chromatography). The cis-Pt(NH3) 2 fragment was not present in these adducts (the dominant product for cisplatin was Pt-CopC in which all original ligands were displaced), while bidentate ligands L were retained in LPt-CopC adducts. In the context of t..