Electron spin resonance spectroscopy and liquid chromatography have been used to detect radical formation and fragmentation of polypeptides during photoinhibition of purified major antenna proteins, free of protease contaminants. In the absence of oxygen and light, no radicals were observed and there was no damage to the proteins. Similarly illumination of the apoproteins did not induce any polypeptide fragmentation, suggesting that chlorophyll, light and atmospheric oxygen are all participating in antenna degradation. The use of TEMP and DMPO as spin traps showed that protein damage initiates with generation Of O-1(2), presumably from a triplet chlorophyll, acting as a Type II photosensitizer which attacks directly the amino acids causing a complete degradation of protein into small fragments, without the contribution of proteases. Through the use of scavengers, it was shown that superoxide and H2O2 were not involved initially in the reaction mechanism. A higher production of radicals was observed in trimers than in monomeric antenna, while radical production is strongly reduced when antennae were organized in the photosystem 11 (PSII) complex. Thus, monomerization of antennae as well as their incorporation into the PSII complex seem to represent physiologically protected forms. A comparison is made of the photoinhibition mechanisms of different photosynthetic systems. (C) 2003 Elsevier B.V. All rights reserved.

Rinalducci, S., Pedersen, J.Z., & Zolla, L. (2004). Formation of radicals from singlet oxygen produced during photoinhibition of isolated light-harvesting proteins of photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS, 1608(1), 63-73 [10.1016/j.bbabio.2003.10.009].

Formation of radicals from singlet oxygen produced during photoinhibition of isolated light-harvesting proteins of photosystem II

PEDERSEN, JENS ZACHO;
2004

Abstract

Electron spin resonance spectroscopy and liquid chromatography have been used to detect radical formation and fragmentation of polypeptides during photoinhibition of purified major antenna proteins, free of protease contaminants. In the absence of oxygen and light, no radicals were observed and there was no damage to the proteins. Similarly illumination of the apoproteins did not induce any polypeptide fragmentation, suggesting that chlorophyll, light and atmospheric oxygen are all participating in antenna degradation. The use of TEMP and DMPO as spin traps showed that protein damage initiates with generation Of O-1(2), presumably from a triplet chlorophyll, acting as a Type II photosensitizer which attacks directly the amino acids causing a complete degradation of protein into small fragments, without the contribution of proteases. Through the use of scavengers, it was shown that superoxide and H2O2 were not involved initially in the reaction mechanism. A higher production of radicals was observed in trimers than in monomeric antenna, while radical production is strongly reduced when antennae were organized in the photosystem 11 (PSII) complex. Thus, monomerization of antennae as well as their incorporation into the PSII complex seem to represent physiologically protected forms. A comparison is made of the photoinhibition mechanisms of different photosynthetic systems. (C) 2003 Elsevier B.V. All rights reserved.
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore BIO/10
English
Con Impact Factor ISI
ESR; Light-harvesting complex; Photoinhibition; Protein degradation; Reactive oxygen species; Singlet oxygen
Rinalducci, S., Pedersen, J.Z., & Zolla, L. (2004). Formation of radicals from singlet oxygen produced during photoinhibition of isolated light-harvesting proteins of photosystem II. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS, 1608(1), 63-73 [10.1016/j.bbabio.2003.10.009].
Rinalducci, S; Pedersen, Jz; Zolla, L
Articolo su rivista
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2108/30640
Citazioni
  • ???jsp.display-item.citation.pmc??? 24
  • Scopus 87
  • ???jsp.display-item.citation.isi??? 88
social impact