2000年
Functional characteristics of chlorophyll d-predominating photosynthetic apparatus in intact cells of Acaryochloris marina
PHOTOSYNTHESIS RESEARCH
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- ,
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- 巻
- 65
- 号
- 3
- 開始ページ
- 269
- 終了ページ
- 277
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1023/A:1010637631417
- 出版者・発行元
- KLUWER ACADEMIC PUBL
Functional organization of the photosynthetic apparatus in the unique chlorophyll d-predominating prokaryote, Acaryochloris marina, was studied using polarographic measurements of single-turnover flash yields, action spectra and optical cross sections for PS-specific reactions. O-2 evolution was indicative of PS II activity, while reversible photoinhibition of respiratory O-2 uptake under aerobic conditions in the presence of DCMU and H-2 photoevolution by anaerobically adapted cells were the indicatives of PS I activity. O-2 evolution in the cells upon single-turnover flashes followed the normal S-state cycle with a period-4 oscillation. Analysis of action spectra for the partial reactions of photosynthesis revealed that: (1) distinct spectral forms of Chl d are nonuniformly distributed between PS I and PS II, e.g. Chl d-695 and Chl d-735 are preferentially located in PS II and PS I, respectively; (2) a minor fraction of Chl a in the cells belongs mostly to PS II; (3) biliproteins transfer excitation energy both to PS II and, with a lower efficiency, PS I; (4) the efficiency of energy transfer from biliproteins to PS II depends on the light quality growth conditions and is larger in white light (WL)-grown cells compared to the red light (RL)-grown cells. Content of functional O-2 evolving PS II centers decreases 2 times in the RL-grown cells relative to the WL-grown cells, whereas content of competent PS I centers involved in photoinhibition of respiration remains almost the same in both the cultures. The effective antenna size of PS I was estimated to be 80-90 Chl d including 3-10 molecules absorbing at 735 nm. The effective optical cross-section of PS II corresponded to 90-100 Chl d and, presumably, 4 Chl a + 2 Pheo a [Mimuro et al. (1999) Biochim Biophys Acta 1412: 37-46]. Optical cross-section measurements indicated that the functional PS II units of A. marina attach one rod of four hexameric units of biliproteins.
- リンク情報
- ID情報
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- DOI : 10.1023/A:1010637631417
- ISSN : 0166-8595
- Web of Science ID : WOS:000167853900007