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Light-induced absorption spectra of the D1-D2-cytochrome b559 complex of the Photosystem II: Effect of methyl viologen concentration

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dc.creator Yruela Guerrero, Inmaculada
dc.creator Torrado Plou, Elena
dc.creator Roncel Gil, Mercedes
dc.creator Picorel Castaño, Rafael
dc.date 2008-04-30T14:10:51Z
dc.date 2008-04-30T14:10:51Z
dc.date 2001-03
dc.date.accessioned 2017-01-31T01:06:38Z
dc.date.available 2017-01-31T01:06:38Z
dc.identifier Photosynthesis Research 67(3): 199-206, 2001
dc.identifier 0166-8595 (print version)
dc.identifier 1573-5079 (electronic version)
dc.identifier http://hdl.handle.net/10261/3956
dc.identifier 10.1023/A:1010682416016
dc.identifier.uri http://dspace.mediu.edu.my:8181/xmlui/handle/10261/3956
dc.description The definitive version is available at: http://www.springerlink.com/content/l304h18744r52202/fulltext.html
dc.description The light-induced difference absorption spectra associated to the photo-accumulation of reduced pheophytin a were studied in the isolated D1–D2–Cyt b559 complex in the presence of variable methyl viologen concentrations and different illumination conditions under anaerobiosis. Depending on the methyl viologen/reaction centre ratio, the relative intensities of the spectral bands at 681.5±0.5, 667.0±0.5 and 542.5±0.5 nm were modified. The reduced pheophytin a located at the D1-branch of the complex absorbs at 681.7±0.5 nm, and at least two additional pigment species contribute to the Qy band of the difference absorption spectra with maxima at 667.0±0.5 and 680.5±0.5 nm. We propose the additional species correspond to a peripheral chlorophyll a and the pheophytin a located at the D2-branch of the complex, respectively. The blue absorbing chlorophyll at 667 nm is susceptible to chemical redox changes with a midpoint reduction potential of +470 mV. The Qx absorption bands of both pheophytins localised at the D2- and D1-branch of the D1–D2–Cyt b559 complex were at 540.7±0.5 and 542.9±0.5, respectively. The results indicated that the two pheophytin molecules can be photoreduced in the D1–D2–Cyt b559 complex in certain experimental conditions.
dc.description This work was supported by the Dirección General de Investigación Científica y Técnica (Grant PB98-1632).
dc.description Peer reviewed
dc.format 321506 bytes
dc.format application/pdf
dc.language eng
dc.publisher Springer
dc.rights openAccess
dc.subject Absorption
dc.subject Chlorophyll
dc.subject Pheophytin
dc.subject Photosystem II
dc.subject Reaction centre
dc.subject Spectroscopy
dc.title Light-induced absorption spectra of the D1-D2-cytochrome b559 complex of the Photosystem II: Effect of methyl viologen concentration
dc.type Artículo


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