Pigment content of D1-D2-cytochrome b{sub 559} reaction center preparations after removal of CP47 contamination: An immunological study
- National Renewable Energy Lab., Golden, CO (United States); and others
Isolated D1-D2-cytochrome b{sub 559} photosystem II reaction center preparations with pigment stoichiometry higher than 4 chlorophylls per 2 pheophytins can be contaminated with CP47 proximal antenna complex. Reaction centers prepared by a modification of the Nanba-Satoh procedure and containing about 6 chlorophylls per 2 pheophytins showed immuno-cross-reactivity when probed with a monoclonal antibody raised against the CP47 polypeptide. Furthermore, they could be fractionated successfully by Superose-12 sieve chromatography into two different populations. The first few fractions off the column contained a more definitive 435 nm shoulder corresponding to increased chlorophyll content, and showed strong immuno-cross-reactivity with the CP47 antibody. The peak fractions off the column displayed a less prominent 435 nm shoulder, and did not cross-react with the antibody. Moreover, when a 6-chlorophyll preparation was mixed with Sepharose beads coupled to CP47 antibody. the eluted material corresponded to a preparation of about 4 chlorophylls per 2 pheophytins and did not show any cross-reaction with the antibody against CP47. The amount of CP47 protein in the 6-chlorophyll preparation as quantitated using Coomassie Blue staining or from gel blots was sufficient to account for most of the extra 2 chlorophylls. We conclude that D1-D2-cytochrome b{sub 559} preparations containing more than 4 chlorophylls per 2 pheophytins can be contaminated with small amounts of CP47-D1-D2-Cyt b{sub 559} complex and that native photosystem II reaction centers contain 4 core chlorophylls per 2 pheophytins. 38 refs., 4 figs., 1 tab.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC36-83CH10093
- OSTI ID:
- 430190
- Journal Information:
- Biochemistry (Eaton), Vol. 34, Issue 46; Other Information: PBD: 21 Nov 1995
- Country of Publication:
- United States
- Language:
- English
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