title: An anion binding site in the active centre of phospholipase C from Bacillus cereus.
abstract: The bi-Zn2+-enzyme phospholipase C (Bacillus cereus) is readilly inhibited by univalent anions. N.m.r. studies on the 113Cd-substituted enzyme showed the presence of an inert and a perturbable metal, neither of which seemed affected by I-. X-ray crystallographic analysis showed the binding of one I- to the enzyme 4.8 A from the nearest metal (too far for a metal-halide bond). Phospholipase C contains an arginine residue apparently necessary for substrate binding and I- partially protected against inactivation by an arginine reagent. Thus an arginine residue may represent the binding site for univalent anions in the enzyme active centre.
mesh_terms: D000838:Anions; D001409:Bacillus cereus / Q000201:enzymology*; D001665:Binding Sites; D002104:Cadmium; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008958:Models, Molecular; D010740:Phospholipases / Q000378:metabolism*; D011487:Protein Conformation; D010738:Type C Phospholipases / Q000378:metabolism*; D014961:X-Ray Diffraction; D015032:Zinc / Q000032:analysis
chemical_list: D000838:Anions; D002104:Cadmium; D010740:Phospholipases; D010738:Type C Phospholipases; D015032:Zinc