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Titolo:
Modeling the bacterial photosynthetic reaction center. 4. The structural, electrochemical, and hydrogen-bonding properties of 22 mutants of Rhodobacter sphaeroides
Autore:
Hughes, JM; Hutter, MC; Reimers, JR; 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:
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
fascicolo: 35, volume: 123, anno: 2001,
pagine: 8550 - 8563
SICI:
0002-7863(20010905)123:35<8550:MTBPRC>2.0.ZU;2-#
Fonte:
ISI
Lingua:
ENG
Soggetto:
PRIMARY ELECTRON-DONOR; VIBRATIONAL STARK SPECTROSCOPY; BACTERIOCHLOROPHYLL-BACTERIOPHEOPHYTIN DIMER; VIRIDIS REACTION CENTERS; RHODOPSEUDOMONAS-VIRIDIS; EXCITED-STATES; CHARGE SEPARATION; FREE-ENERGY; AB-INITIO; SAC-CI;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Physical, Chemical & Earth Sciences
Citazioni:
85
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.M. Hughes et al., "Modeling the bacterial photosynthetic reaction center. 4. The structural, electrochemical, and hydrogen-bonding properties of 22 mutants of Rhodobacter sphaeroides", J AM CHEM S, 123(35), 2001, pp. 8550-8563

Abstract

Site-directed mutagenesis has been employed by a number of groups to produce mutants of bacterial photosynthetic reaction centers, with the aim of tuning their operation by modifying hydrogen-bond patterns in the close vicinity of the "special pair" of bacteriochlorophylls P drop PLPM. Direct X-raystructural measurements of the consequences of mutation are rare. Attention has mostly focused on effects on properties such as carbonyl stretching frequencies and midpoint potentials to infer indirectly the induced structural modifications. In this work, the structures of 22 mutants of Rhodobactersphaeroides have been calculated using a mixed quantum-mechanical molecular-mechanical method by modifying the known structure of the wild type. We determine (i) the orientation of the 2a-acetyl groups in the wild type, FY(M197), and FH(M197) series mutants of the neutral and oxidized reaction center, (ii) the structure of the FY(M197) mutant and possible water penetration near the special pair, (iii) that significant protein chain distortions are required to assemble some M160 series mutants (LS(M160), LN(M160), LQ(M160), and LH(M160) are considered), (iv) that there is competition for hydrogen-bonding between the 9-keto and 10a-ester groups for the introduced histidine in LH(L131) mutants, (v) that the observed midpoint potential of P for HL(M202) heterodimer mutants, including one involving also LH(M160), can be correlated with the change of electrostatic potential experienced at PL,(vi) that hydrogen-bond cleavage may sometimes be induced by oxidation of the special pair, (vii) that the OH group of tyrosine M210 points away fromPM, and (viii) that competitive hydrogen-bonding effects determine the change in properties of NL(L166) and NH(L166) mutants. A new technique is introduced for the determination of ionization energies at the Koopmans level from QM/MM calculations, and protein-induced Stark effects on vibrational frequencies are considered.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/12/20 alle ore 14:57:36