Annual progress report, December 1, 1979-November 30, 1980
Structure and function in photosynthetic membranes and their components continue to be studied, principally with Rhodopseudomonas sphaeroides. We have discovered how to remove bacteriochlorophyll (bchl) from a specific binding site in the antenna pigment-protein complex B850, and to replace the bchl without denaturing the complex. This has never before been achieved for any photosynthetic chlorophyllprotein complex. It opens a substantial vista of experiments designed to elucidate the nature of the binding site. Our analyses of the B850 and B875 complexes cast doubt on the accepted ratios of bchl components, carotenoids and protein and hence on models based on these ratios. We have shown that Rp. sphaeroides contains a specific second quinone (Q/sub b/) in contact with the primary photochemical electron acceptor (Q/sub a/) and distinct from the molecules of a larger pool of quinone. We have resolved conflicting reports about the polypeptide composition of reaction centers from Rhodopseudomonas viridis. We have new data on the orientation, relative to the photosynthetic membrane, of cytochrome 552 in Rp. viridis and of the shifting component of carotenoid in Rp. sphaeroides. We have constructed and are using a new circular dichroism spectrometer.
- Research Organization:
- Cornell Univ., Ithaca, NY (United States)
- DOE Contract Number:
- AS02-76ER03162
- OSTI ID:
- 6702659
- Report Number(s):
- COO-3162-53; COO-3162-54(App.B)
- Country of Publication:
- United States
- Language:
- English
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Isolation and characterization of the pigment-protein complexes of Rhodopseudomonas sphaeroides by lithium dodecyl sulfate/polyacrylamide gel electrophoresis
B850 pigment-protein complex of Rhodopseudomonas sphaeroides: binding of bacteriochlorophyll
Related Subjects
CELL MEMBRANES
MOLECULAR STRUCTURE
PHOTOSYNTHESIS
RESEARCH PROGRAMS
CAROTENOIDS
CHEMICAL BONDS
CHLOROPHYLL
COMPLEXES
CYTOCHROMES
PHOTOSYNTHETIC BACTERIA
PROTEINS
RHODOPSEUDOMONAS
BACTERIA
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CHEMICAL REACTIONS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
MEMBRANES
MICROORGANISMS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHYTOCHROMES
PIGMENTS
PORPHYRINS
SYNTHESIS
TERPENES
550300* - Cytology