Conformational and Electronic Properties of a Microperoxidase in Aqueous Solution: A Computational Study

Carla Di Teodoro ^{1 2}, Massimiliano Aschi ^{1 *}, Andrea Amadei ³, Danilo Roccatano ⁴, Francesco Malatesta ⁵, Luca Ottaviano ²

¹Dipartimento di Chimica, Ingegneria Chimica e Materiali, Università dell'Aquila, via Vetoio 10, 67010 l'Aquila, Italy, Fax: (+39) 0862-433-753
²Dipartimento di Fisica, Università dell'Aquila via Vetoio 10, 67010 l'Aquila, Italy
³Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Roma, Italy
⁴International University Bremen School of Engineering and Science, Campus Ring I, 28579 Bremen, Germany
⁵Dipartimento di Biologia di Base ed Applicata, Università dell'Aquila, via Vetoio 10, 67010 l'Aquila, Italy

email: Massimiliano Aschi (aschi@caspur.it)

FULL TEXT

Keywords

electron transfer • electronic excitation • molecular dynamics • photochemistry • solvent effects

Abstract

A theoretical study of the conformational properties of a small heme peptide in aqueous solution is carried out by classical, long-timescale molecular dynamics simulations. The electronic properties of this species, that is, the relative energies of its excited electronic states and the redox potential, are reproduced and related to the conformational behavior using the perturbed matrix method and basic statistical mechanics. Our results show an interesting coupling between the conformational transitions and the electronic properties. These investigations, beyond the biophysically relevant results addressing the long-standing question of the actual role of the enzyme structure on the enzyme activity, are also of some methodological interest since they offer a further computational perspective for incuding the electronic degrees of freedom into the modeling of rather complex molecular systems.