| Popis: |
Disintegration of the Photosystem II (PS II) reaction center core complex (RC complex) from the spinach PS II by using mild detergents resulted in success of isolating three types of subcomplex (complexes 1–3), retaining their prosthetic groups and two pigments-binding subunit polypeptides with molecular masses of 47 kDa and 43 kDa. The polypeptide compositions of the three complexes isolated were 47 kDa/43 kDa/D1 cytochrome b-559 in complex 1, 47 kDa/D1/D2-cytochrome b-559 in complex 2 and D1/D2/cytochrome b-559 in complex 3. The complex 3 was confirmed to have four Chl a, two pheophytins a, one β-carotene and one plastoquinone A-9 (PQA) in molar ratio. These numbers were essentially the same as in the results reported by Nanba and Satoh on their D1/D2/cytochrome b-559 particle, except for PQA. All of the three subcomplexes isolated in the present work preserved one PQA at least. However, instead of the photoinduced charge separation between P-680 and QA the formation of the triplet state P-680 as a result of recombination of photoinduced P-680+ and Pheo a was observed in the three preparations. The decay time of the triplet state was determined as 25 μs. Evidence suggesting that the reconstitution of QA function was performed in complex 1 and complex 2 with the thylakoid lipids and thylakoid lipids plus PQA, respectively, was obtained. |
