Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Molecular dynamics study of bacteriorhodopsin and the purple membrane
Autore:
Baudry, J; Tajkhorshid, E; Molnar, F; Phillips, J; Schulten, K;
Indirizzi:
Univ Illinois, Beckman Inst, Urbana, IL 61801 USA Univ Illinois Urbana ILUSA 61801 ois, Beckman Inst, Urbana, IL 61801 USA Univ Illinois, Dept Phys, Urbana, IL 61801 USA Univ Illinois Urbana IL USA 61801 linois, Dept Phys, Urbana, IL 61801 USA
Titolo Testata:
JOURNAL OF PHYSICAL CHEMISTRY B
fascicolo: 5, volume: 105, anno: 2001,
pagine: 905 - 918
SICI:
1520-6106(20010208)105:5<905:MDSOBA>2.0.ZU;2-Z
Fonte:
ISI
Lingua:
ENG
Soggetto:
INDUCED CONFORMATIONAL-CHANGES; CYTOCHROME-C-OXIDASE; NEUTRON-SCATTERING; WATER-MOLECULES; ELECTRON CRYSTALLOGRAPHY; ANGSTROM RESOLUTION; STRUCTURAL-CHANGES; SCHIFF-BASE; ENERGY; PHOTOISOMERIZATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
61
Recensione:
Indirizzi per estratti:
Indirizzo: Schulten, K Univ Illinois, Beckman Inst, Urbana, IL 61801 USA Univ Illinois Urbana IL USA 61801 Inst, Urbana, IL 61801 USA
Citazione:
J. Baudry et al., "Molecular dynamics study of bacteriorhodopsin and the purple membrane", J PHYS CH B, 105(5), 2001, pp. 905-918

Abstract

Vectorial proton translocation through membranes is a fundamental energy conversion process in biological cells. Bacteriorhodopsin (bR) is a membraneprotein that acts as a light-driven, voltage-sensitive proton pump in the purple membrane (PM) of Halobacterium salinarum and achieves its biologicalfunction by cycling through a reaction sequence that includes ultrafast (similar to 500 fs) events, intermediate (mus) as well as slow (similar to 10ms) steps. bR is of utmost simplicity in comparison with other proton translocating bioenergetic proteins and, therefore, constitutes an ideal model for the study of this process. The PM involves a highly structured supramolecular organization and is fundamental fur the in vivo functioning of bR. Over the last 10 years, crystal structures of bR have become available at increasing resolution. The most recent structures resolve many of the lipids of the PM and provide atomic level detail of bR at below 2 Angstrom resolution. Fundamental for an understanding of the function of bR is internal water that participates in proton pumping. Several water molecules have been resolved now crystallographically in two channels, on the extracellular and on the intracellular side of bR, We show that free energy perturbation theory can place water molecules in bR, with results that compare well with theobserved water molecules, and we apply the method to predict water movement during bR's photocycle, A preliminary simulation illustrates that water molecules may indeed be displaced during the photocycle, after retinal undergoes an all-trans --> 13-cis isomerization, and that this displacement may constitute a mechanism for proton pumping. A key advance reported in this feature article is the integration of the available bR structures into a model for the entire PM. This hexagonally periodic, lamellar model has been hydrated and refined through a constant pressure molecular dynamics simulation. The resulting structure connects extracellular bulk water with water molecules and key side groups in the interior of bR, permitting a seamless overall description of the proton path in the PM, from intracellular to extracellular space. For the first time, a complex cellular reaction can be accounted for in full atomic detail in its complete native environment.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/04/20 alle ore 15:29:19