Theoretical density functional theory studies on interactions of small biologically active molecules with isolated heme group

doi:10.1002/jcc.20598

Theoretical density functional theory studies on ...

Bibliographic description

title:	Theoretical density functional theory studies on interactions of small biologically active molecules with isolated heme group
author:	Rutkowska-Żbik Dorota, Witko Małgorzata, Stochel Grażyna
Journal title:	Journal of Computational Chemistry
volume:	28
issue:	4
date of publication:	2007
pages:	825-831
ISSN:	0192-8651
eISSN:	1096-987X
DOI:	10.1002/jcc.20598
language:	English
Journal language:	English
abstract in english:	We present ab-initio density functional theory studies on the interactions of small biologically active molecules, namely NO, CO, O2, H2O, and NOmath image with the full-size heme group. Our results show that the small molecule–iron bond is the strongest in carbonyl and the weakest in nitrite system. Trans influence induced by NO binding to the five-coordinate heme complex is shown. Nitric oxide in the resulting complex might be described as NO−. The differences among the small ligands of XO type (CO, NO, O2), and their distant chemical behavior from H2O and NOmath image ligands in binding to the Fe(II) ion, are shown. Moreover, the role of the heme ring as a reservoir of electrons in the studied complexes is invoked. The analysis of the parameters defining the iron–histidine bond indicates that this bond is longer and weaker in nitrosyl and carbonyl complexes than in the other systems. Our findings support the proposed mechanism of soluble guanylate cyclase (sGC) activation and suggest that the first step of sGC activation by CO may be the same as during the activation by NO. Obtained results are then compared with the data concerning smaller model of the heme, the porphyrin complexes, available in the literature.
keywords in english:	bioinorganic chemistry, heme, density functional calculations, ligand-binding, nitric oxide
affiliation:	Wydział Chemii : Zakład Chemii Nieorganicznej
type:	journal article
subtype:	academic paper