Isolation and characterization of photosynthetic reaction centers from Rhodopseudomonas capsulata and Rhodopseudomonas sphaeroides
Reaction centers were isolated by affinity chromatography on equine cytochrome C. Peripheral proteins were removed with 0.05% LDAO. Absorption and EPR spectra and bleaching assays indicate that the reaction centers retained their electron donors and acceptors in the native environment. Three reaction center polypeptides were isolated and submitted for amino-terminal sequence determination. By comparing these sequences to those deduced from DNA, it was established that the M and L subunits are post-translationally modified to remove the aminoterminal Met, whereas the H subunit is not. Inhibition of O/sub 2/ evolution in photosystem II particles from spinach by naphthoquinone derivatives show O/sub 2/ inhibition by bromomethyl and acetoxymethyl derivatives but not with hydroxymethyl derivatives. Inhibition by acetoxymethyl derivatives in irreversible and dependent on illumination suggesting that reduction of the quinone is necessary. Therefore acetoxymethyl derivatives may be useful as suicide reagents for labelling quinone binding sites. Procedures were developed to extract one or both of the quinones present in reaction centers and preserve the integrity of the co-factor binding sites. The H and M subunits were cleaned using furmic acid. Both fragments were isolated from the H subunit, while the larger fragment was isolated from the M subunit. Electrophoretic mobilities of the isolated fragments agrees well with the expected molecular weights. The L subunit was digested with Staphylococcus areus vs protease. The pattern obtained was consistant with the potential sites of cleavage, but it was not possible to assign cleavage sites unambiguously. 112 references, 37 figures, 2 tables.
- Research Organization:
- Lawrence Berkeley Lab., CA (USA)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6414236
- Report Number(s):
- LBL-18375; ON: DE85000623
- Resource Relation:
- Other Information: Portions are illegible in microfiche products. Thesis
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
RHODOPSEUDOMONAS
PHOTOSYNTHETIC REACTION CENTERS
AMINO ACID SEQUENCE
BIOCHEMICAL REACTION KINETICS
ELECTROPHORESIS
EXPERIMENTAL DATA
INHIBITION
OXYGEN
PHOTOCHEMICAL REACTIONS
PRODUCTION
QUINONES
VISIBLE RADIATION
AROMATICS
BACTERIA
CHEMICAL REACTIONS
DATA
ELECTROMAGNETIC RADIATION
ELEMENTS
INFORMATION
KINETICS
MICROORGANISMS
MOLECULAR STRUCTURE
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
RADIATIONS
REACTION KINETICS
550200* - Biochemistry
550700 - Microbiology