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Titolo:
Directed energy "Funneling" mechanism for heme cooling following ligand photolysis or direct excitation in solvated carbonmonoxy myoglobin
Autore:
Sagnella, DE; Straub, JE;
Indirizzi:
Boston Univ, Dept Chem, Boston, MA 02215 USA Boston Univ Boston MA USA 02215 ton Univ, Dept Chem, Boston, MA 02215 USA
Titolo Testata:
JOURNAL OF PHYSICAL CHEMISTRY B
fascicolo: 29, volume: 105, anno: 2001,
pagine: 7057 - 7063
SICI:
1520-6106(20010726)105:29<7057:DE"MFH>2.0.ZU;2-N
Fonte:
ISI
Lingua:
ENG
Soggetto:
MOLECULAR-DYNAMICS SIMULATIONS; VIBRATIONAL-RELAXATION; INFRARED-SPECTROSCOPY; COLLECTIVE MOTIONS; PROTEIN MOTION; IR ABSORBENCY; TIME SCALES; MONOXIDE; SOLVENT; PHOTODISSOCIATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
49
Recensione:
Indirizzi per estratti:
Indirizzo: Straub, JE Boston Univ, Dept Chem, 590 Commonwealth Ave, Boston, MA 02215 USA Boston Univ 590 Commonwealth Ave Boston MA USA 02215 02215 USA
Citazione:
D.E. Sagnella e J.E. Straub, "Directed energy "Funneling" mechanism for heme cooling following ligand photolysis or direct excitation in solvated carbonmonoxy myoglobin", J PHYS CH B, 105(29), 2001, pp. 7057-7063

Abstract

The kinetic energy relaxation of photolyzed heme in myoglobin was investigated using molecular dynamics simulations. Following photolysis, the heme was found to lose most of its excess kinetic energy within 10 ps. The kinetic energy decay was found to be a single exponential with a time constant of5.9 ps in agreement with the experimental observations of Lim, Jackson andAnfinrud [J. Phys. Chem. 100, 12 043 (1996)]. The flow of kinetic energy was found to occur primarily through nonbonded contacts. The heme doming motion causes collisions with nearby residues and large scale collective motion in the protein. However, the strong electrostatic interaction of the isoproprionate side chains, and the solvating water appears to be the single most important "doorway" for dissipation of excess kinetic energy in the heme. Those water molecules in close contact with the heme side chains were found to "warm" in less than 1.0 ps. Direct energy transfer from the heme to the protein is found to occur by "through projectile" (ligand collisions with the distal heme pocket residue), "through bond" (heme bond to proximal histidine), and "through space" (nonbonded collisional) channels. These results provide strong evidence for a spatially directed "funneling" of kinetic energy through the heme side chains to the surrounding solvent suggested byHochstrasser and co-workers.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 26/01/20 alle ore 16:11:37