کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1943589 1052674 2007 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Association of chlorophyll a/b-binding Pcb proteins with photosystems I and II in Prochlorothrix hollandica
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک دانش گیاه شناسی
پیش نمایش صفحه اول مقاله
Association of chlorophyll a/b-binding Pcb proteins with photosystems I and II in Prochlorothrix hollandica
چکیده انگلیسی

Action spectra for photosystem II (PSII)-driven oxygen evolution and of photosystem I (PSI)-mediated H2 photoproduction and photoinhibition of respiration were used to determine the participation of chlorophyll (Chl) a/b-binding Pcb proteins in the functions of pigment apparatus of Prochlorothrix hollandica. Comparison of the in situ action spectra with absorption spectra of PSII and PSI complexes isolated from the cyanobacterium Synechocystis 6803 revealed a shoulder at 650 nm that indicated presence of Chl b in the both photosystems of P. hollandica. Fitting of two action spectra to absorption spectrum of the cells showed a chlorophyll ratio of 4:1 in favor of PSI. Effective antenna sizes estimated from photochemical cross-sections of the relevant photoreactions were found to be 192 ± 28 and 139 ± 15 chlorophyll molecules for the competent PSI and PSII reaction centers, respectively. The value for PSI is in a quite good agreement with previous electron microscopy data for isolated Pcb–PSI supercomplexes from P. hollandica that show a trimeric PSI core surrounded by a ring of 18 Pcb subunits. The antenna size of PSII implies that the PSII core dimers are associated with ∼ 14 Pcb light-harvesting proteins, and form the largest known Pcb–PSII supercomplexes.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - Bioenergetics - Volume 1767, Issue 6, June 2007, Pages 801–806
نویسندگان
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