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Titolo:
Nature of the special-pair radical cation in bacterial photosynthesis
Autore:
Reimers, JR; Hutter, MC; Hughes, JM; Hush, NS;
Indirizzi:
Univ Sydney, Sch Chem, Sydney, NSW 2006, Australia Univ Sydney Sydney NSWAustralia 2006 h Chem, Sydney, NSW 2006, Australia Univ Sydney, Dept Biochem, Sydney, NSW 2006, Australia Univ Sydney SydneyNSW Australia 2006 iochem, Sydney, NSW 2006, Australia
Titolo Testata:
INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY
fascicolo: 6, volume: 80, anno: 2000,
pagine: 1224 - 1243
SICI:
0020-7608(200012)80:6<1224:NOTSRC>2.0.ZU;2-I
Fonte:
ISI
Lingua:
ENG
Soggetto:
PRIMARY ELECTRON-DONOR; SPHAEROIDES REACTION CENTERS; FREQUENCY VIBRATIONAL-MODES; VIRIDIS REACTION CENTERS; RHODOBACTER-SPHAEROIDES; RHODOPSEUDOMONAS-VIRIDIS; CHARGE SEPARATION; EXCITED-STATES; SAC-CI; BACTERIOCHLOROPHYLL DIMER;
Keywords:
photosynthesis; purple bacteria; QM/MM; mutants; bacteriochlorophyll; midpoint potential; special pair; vibronic coupling; vibrational analysis;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
82
Recensione:
Indirizzi per estratti:
Indirizzo: Reimers, JR Univ Sydney, Sch Chem, Sydney, NSW 2006, Australia Univ Sydney Sydney NSW Australia 2006 ey, NSW 2006, Australia
Citazione:
J.R. Reimers et al., "Nature of the special-pair radical cation in bacterial photosynthesis", INT J QUANT, 80(6), 2000, pp. 1224-1243

Abstract

Primary charge separation in bacterial photosynthesis occurs at the "special pair," a bacteriochlorophyll dimer that, on optical excitation, ejects an electron to become the special-pair radical cation. Understanding the nature of this species is important to both the charge separation process itself and details of subsequent steps including charge recombination. Electronspin resonance (ESR)-based studies have led to the conclusion that the positive charge is delocalized over both bacteriochlorophyll monomers, the degree of delocalization being affected by site-directed mutagenesis. However,Breton et al. have observed charge-transfer electronic absorption spectra (centred at ca. 2500 cm(-1)), which, when interpreted using standard electron-transfer theory, indicate strong charge localization on just one of the bacteriochlorophylls. We present a complex computational strategy aimed at resolving this issue through vibronic coupling analysis of the high- and low-resolution spectra using a priori computed vibrational analyses, quantum chemical calculation of the strengths of a variety of key interactions, quantum mechanical/molecular mechanical (QM/MM) calculation of the structure of over 20 mutant reaction centers, calculation and interpretation of the observed midpoint potentials, analyses relevant to ESR and related spectroscopies, etc. The current state of progress is described, leading to a consistent picture that includes almost all available experimental data. (C) 2000 John Wiley & Sons, Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 24/11/20 alle ore 21:42:17