title: Low-temperature magnetic circular dichroism investigation of the active site of chloroperoxidase.
abstract: Magnetic circular dichroism (MCD) spectra for near UV and visible spectral regions of chemically reduced chloroperoxidase from Caldariomyces fumago have been recorded at temperatures from near 293 to 2.15 K. The spectra of reduced chloroperoxidase at 4.2 K were compared with those of photolysis products of its carbon monoxide complexes. Obtained results give evidence for high rigidity of the active site in chloroperoxidase and strongly suggest that thiolate is a protein-derived ligand of the heme iron in the reduced enzyme. The unusual high-spin ferrohemoproteins temperature dependence of the Soret MCD closely resembles that of the substrate-bound cytochrome P-450cam.
authors.affiliation: Engelhardt Institute of Molecular Biology, Academy of Sciences of Russia, Moscow.
authors.forename: E G
authors.initials: EG
authors.lastname: Yarmola
authors.forename: Y A
authors.initials: YA
authors.lastname: Sharonov
mesh_terms: D001665:Binding Sites; D002248:Carbon Monoxide / Q000737:chemistry; D002711:Chloride Peroxidase / Q000737:chemistry*; D002942:Circular Dichroism; D003080:Cold Temperature; D006418:Heme; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D003904:Mitosporic Fungi / Q000201:enzymology; D010084:Oxidation-Reduction; D010782:Photolysis; D011487:Protein Conformation; D013438:Sulfhydryl Compounds / Q000737:chemistry
chemical_list: D008024:Ligands; D013438:Sulfhydryl Compounds; D006418:Heme; D002248:Carbon Monoxide; D002711:Chloride Peroxidase