Molecular weight determination of an active photosystem I preparation from a thermophilic cyanobacterium, Synechococcus elongatus

Journal Article · Tue Feb 06 00:00:00 EST 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00457a018· OSTI ID:6828382

Schafheutle, M E; Setlikova, E; Timmins, P A; Johner, H; Gutgesell, P; Setlik, I; Welte, W ^[1]

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1. Institut fuer Biophysik und Strahlenbiologie, Freiburg (Germany, F.R.)

An active photosystem I (PSI) complex was isolated from the thermophilic cyanobacterium Synechococcus elongatus by a procedure consisting of three steps: First, extraction of photosystem II from the thylakoids by a sulfobetaine detergent yields PSI-enriched membranes. Second, the latter are treated with Triton X-100 to extract PSI particles, which are further purified by preparative isoelectric focusing. Third, anion-exchange chromatography is used to remove contaminating phycobilisome polypeptides. The purified particles show three major bands in sodium dodecyl sulfate gel electrophoresis of apparent molecular mass of 110, 15, and 10 kDa. Charge separation was monitored by the kinetics of flash-induced absorption changes at 820 nm. A chlorophyll/P700 ratio of 60 was found. When the particles are stored at 4 degrees C, charge separation was stable for weeks. The molecular mass of the PSI particles, determined by measurement of zero-angle neutron scattering intensity, was 217,000 Da. The PSI particles thus consist of one heterodimer of the 60-80-kDa polypeptides and presumably one copy of the 15- and 10-kDa polypeptides, respectively.

• OSTI ID: 6828382
• Journal Information: Biochemistry; (USA), Vol. 29:5; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CYANOBACTERIA
PHOTOSYNTHETIC REACTION CENTERS
MOLECULAR WEIGHT
AMINO ACIDS
CHLOROPHYLL
ELECTRON MICROPROBE ANALYSIS
ION EXCHANGE CHROMATOGRAPHY
NEUTRONS
BARYONS
CARBOXYLIC ACIDS
CHEMICAL ANALYSIS
CHROMATOGRAPHY
ELEMENTARY PARTICLES
FERMIONS
HADRONS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
MICROANALYSIS
MICROORGANISMS
NUCLEONS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHYTOCHROMES
PIGMENTS
PORPHYRINS
PROTEINS
SEPARATION PROCESSES
550201* - Biochemistry- Tracer Techniques