title: The action spectrum of Photosystem II photoinactivation in visible light.
abstract: Photosynthesis is always accompanied by light induced damage to the Photosystem II (PSII) which is compensated by its subsequent repair. Photoinhibition of PSII is a complex process, balancing between photoinactivation, protective and repair mechanisms. Current understanding of photoinactivation is limited with competing hypotheses where the photosensitiser is either photosynthetic pigments or the Mn4CaO5 cluster itself, with little consensus on the mechanisms and consequences of PSII photoinactivation. The mechanism of photoinactivation should be reflected in the action spectrum of PSII photoinactivation, but there is a great diversity of the action spectra reported thus far. The only consensus is that PSII photoinactivation is greatest in the UV region of the electromagnetic spectrum. In this review, the authors revisit the methods, technical constraints and the different action spectra of PSII photoinactivation reported to date and compare them against the diverse mechanisms proposed. Upon critical examination of the reported action spectra, a hybrid mechanism of photoinactivation, sensitised by both photosynthetic pigments and the Mn4CaO5 appears to be the most plausible rationalisation.
authors: Research School of Biology, College of Medicine, Biology and Environment, The Australian National University, Canberra ACT 2601, Australia.
authors: Alonso
authors: A
authors: Zavafer
authors: Research School of Biology, College of Medicine, Biology and Environment, The Australian National University, Canberra ACT 2601, Australia.
authors: Wah Soon
authors: WS
authors: Chow
authors: Research School of Biology, College of Medicine, Biology and Environment, The Australian National University, Canberra ACT 2601, Australia. Electronic address: michael.cheah@anu.edu.au.
authors: Mun Hon
authors: MH
authors: Cheah
mesh_terms: D004789:Enzyme Activation / Q000528:radiation effects; D008027:Light; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D018515:Plant Leaves / Q000201:enzymology / Q000528:radiation effects; D020524:Thylakoids / Q000201:enzymology / Q000528:radiation effects
chemical_list: D045332:Photosystem II Protein Complex