Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Pressure-exploration of the 33-kDa protein from the spinach photosystem IIparticle
Autore:
Ruan, KC; Xu, CH; Yu, Y; Li, J; Lange, R; Bec, N; Balny, C;
Indirizzi:
Chinese Acad Sci, Shanghai Inst Biol Sci, Inst Plant Physiol, Beijing 100864, Peoples R China Chinese Acad Sci Beijing Peoples R China 100864 100864, Peoples R China CNRS, IFR 24, INSERM, U128, Montpellier, France CNRS Montpellier FranceCNRS, IFR 24, INSERM, U128, Montpellier, France Chinese Acad Sci, Shanghai Inst Biol Sci, Inst Biochem & Cell Biol, Beijing 100864, Peoples R China Chinese Acad Sci Beijing Peoples R China 100864 100864, Peoples R China
Titolo Testata:
EUROPEAN JOURNAL OF BIOCHEMISTRY
fascicolo: 9, volume: 268, anno: 2001,
pagine: 2742 - 2750
SICI:
0014-2956(200105)268:9<2742:POT3PF>2.0.ZU;2-U
Fonte:
ISI
Lingua:
ENG
Soggetto:
PHOTOSYNTHETIC OXYGEN-EVOLUTION; DERIVATIVE UV-SPECTROSCOPY; HIGH HYDROSTATIC-PRESSURE; CONFORMATIONAL DRIFT; RIBONUCLEASE-A; DEHYDROGENASE; DENATURATION; CHYMOTRYPSINOGEN; CRYOINACTIVATION; RECONSTITUTION;
Keywords:
conformational changes; hydrostatic pressure; spinach particle; protein denaturation;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
39
Recensione:
Indirizzi per estratti:
Indirizzo: Ruan, KC Chinese Acad Sci, Shanghai Inst Biochem & Cell Biol, 320 Yue YangRd, Shanghai 200031, Peoples R China Chinese Acad Sci 320 Yue Yang Rd Shanghai Peoples R China 200031
Citazione:
K.C. Ruan et al., "Pressure-exploration of the 33-kDa protein from the spinach photosystem IIparticle", EUR J BIOCH, 268(9), 2001, pp. 2742-2750

Abstract

The 33-kDa protein isolated from the spinach photosystem II particle is anideal model to explore high-pressure protein-unfolding. The protein has a very low free energy as previously reported by chemical unfolding studies, suggesting that it must be easy to modulate its unfolding transition by rather mild pressure. Moreover, the protein molecule consists of only one tryptophan residue (Trp241) and eight tyrosine residues, which can be conveniently used to probe the protein conformation and structural changes under pressure using either fluorescence spectroscopy or fourth derivative UV absorbance spectroscopy. The different experimental methods used in the present study indicate that at 20 degreesC and pH 6, the 33-kDa protein shows a reversible two-state unfolding transition from atmospheric pressure to about 180 MPa. This value is much lower than those found for the unfolding of most proteins studied so far. The unfolding transition induces a large red shiftof the maximum fluorescence emission of 34 nm (from 316 nm to 350 nm). Thechange in standard free energy (DeltaG(o)) and in volume (DeltaV) for the transition at pH 6.0 and 20 degreesC are -14.6 kJ.mol(-1) and -120 mL.mol(-1), respectively, in which the DeltaG(o) value is consistent with that obtained by chemical denaturation. We found that pressure-induced protein unfolding is promoted by elevated temperatures, which seem largely attributed tothe decrease in the absolute value of DeltaG(o) (only a minor variation was observed for the DeltaV value). However, the promotion of the unfolding by alkaline pH seems mainly related to the increase in DeltaV without any significant changes in DeltaG(o). It was also found that NaCl significantly protects the protein from pressure-induced unfolding. In the presence of 1 mNaCl, the pressure needed to induce the half-unfold of the protein is shifted to a higher value (shift of 75 MPa) in comparison with that observed without NaCl. Interestingly, in the presence of NaCl, the value of DeltaV is significantly reduced whilst that of DeltaG(o) remains as before. The unfolding-refolding kinetics of the protein has also been studied by pressure-jump, in which it was revealed that both reactions are a two-state transitionprocess with a relatively slow relaxation time of about 10(2) s.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 06/07/20 alle ore 05:50:49