title: Theoretical DFT study of fragmentation and association of heme and hemin.
abstract: The electronic and geometric structures, energy stability, and normal vibrational frequencies of heme, hemine, and their stepwise fragmentation products (with successive loss of two carboxymethyl, four methyl, and two vinyl peripheral groups) in the states with different multiplicity were calculated using the density functional theory (the B3LYP method) with several basis sets. At the same level, the structure and stability of neutral and positively charged dimers of the ferri- and ferroporphyrines were also computed. The computational results are compared with available experimental data. The trends in the behavior of these properties of heme and hemin are analyzed upon the stepwise fragmentation and association and with a change in the multiplicity and external charge. The structure and energetic stability of complexes of the species with molecular oxygen are discussed.
authors.affiliation: Institute of Problems of Chemical Physics, Russian Academy of Sciences, Institutskii prosp. 18, Chernogolovka, Moscow Region, 142432 Russia. charkin@icp.ac.ru
authors.forename: O P
authors.initials: OP
authors.lastname: Charkin
authors.forename: N M
authors.initials: NM
authors.lastname: Klimenko
authors.forename: D O
authors.initials: DO
authors.lastname: Charkin
authors.forename: H-C
authors.initials: HC
authors.lastname: Chang
authors.forename: S-H
authors.initials: SH
authors.lastname: Lin
mesh_terms: D003198:Computer Simulation; D019281:Dimerization; D006418:Heme / Q000737:chemistry*; D006427:Hemin / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D046911:Macromolecular Substances / Q000737:chemistry; D008956:Models, Chemical; D015394:Molecular Structure; D010100:Oxygen / Q000737:chemistry; D011789:Quantum Theory
chemical_list: D007477:Ions; D046911:Macromolecular Substances; D006418:Heme; D006427:Hemin; D010100:Oxygen