Human myeloperoxidase: structure of a cyanide complex and its interaction with bromide and thiocyanate substrates at 1.9 A resolution.Blair-Johnson, M., Fiedler, T., Fenna, R.
(2001) Biochemistry 40: 13990-13997
- PubMed: 11705390
- Primary Citation of Related Structures:
- PubMed Abstract:
- 2.3 Angstrom Resolution X-Ray Crystal Structure of the Bisubstrate Analogue Inhibitor Salicylhydroxamic Acid Bound to Human Myeloperoxidase: A Model for a Prereaction Complex with Hydrogen Peroxide
Davey, C.A.,Fenna, R.E.
(1996) Biochemistry 35: 10967
- Structure of the Green Heme in Myeloperoxidase
Fenna, R.,Zeng, J.,Davey, C.
(1995) Arch.Biochem.Biophys. 316: 653
- Site-Directed Mutagenesis of Human Myeloperoxidase: Further Identification of Residues Involved in Catalytic Activity and Heme Interaction
Jacquet, A.,Garcia-Quintana, L.,Deleersnyder, V.,Fenna, R.,Bollen, A.,Moguilevsky, N.
(1994) Biochem.Biophys.Res.Commun. 202: 73
- X-Ray Crystal Structure of Canine Myeloperoxidase at 3 Angstrom Resolution
Zeng, J.,Fenna, R.E.
(1992) J.Mol.Biol. 226: 185
The 1.9 A X-ray crystal structure of human myeloperoxidase complexed with cyanide (R = 0.175, R(free) = 0.215) indicates that cyanide binds to the heme iron with a bent Fe-C-N angle of approximately 157 degrees, and binding is accompanied by movement ...
The 1.9 A X-ray crystal structure of human myeloperoxidase complexed with cyanide (R = 0.175, R(free) = 0.215) indicates that cyanide binds to the heme iron with a bent Fe-C-N angle of approximately 157 degrees, and binding is accompanied by movement of the iron atom by 0.2 A into the porphyrin plane. The bent orientation of the cyanide allows the formation of three hydrogen bonds between its nitrogen atom and the distal histidine as well as two water molecules in the distal cavity. The 1.85 A X-ray crystal structure of an inhibitory complex with thiocyanate (R = 0.178, R(free) = 0.210) indicates replacement of chloride at a proximal helix halide binding site in addition to binding in the distal cavity in an orientation parallel with the heme. The thiocyanate replaces two water molecules in the distal cavity and is hydrogen bonded to Gln 91. The 1.9 A structures of the complexes formed by bromide (R = 0.215, R(free) = 0.270) and thiocyanate (R = 0.198, R(free) = 0.224) with the cyanide complex of myeloperoxidase show how the presence of bound cyanide alters the binding site for bromide in the distal heme cavity, while having little effect on thiocyanate binding. These results support a model for a single common binding site for halides and thiocyanate as substrates or as inhibitors near the delta-meso carbon of the porphyrin ring in myeloperoxidase.
Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, Miami, Florida 33101, USA.