Open AccessIsolation and quaternary structure of the photosynthetic core of the marine purple sulfur bacterium Chromatium purpuratum
Author(s) -
Pushkin Alexander V.,
Eiserling Frederick A.,
Kerfeld Cheryl A.,
Thornber J.Philip
Publication year - 1993
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1993.tb06509.x
Subject(s) - chromatium , purple bacteria , electron microscope , gel electrophoresis , photosynthetic reaction centre , polyacrylamide gel electrophoresis , agarose , chemistry , centrifugation , analytical chemistry (journal) , chromatography , photosynthesis , biochemistry , optics , enzyme , physics
Based on polyacrylamide/agarose gel electrophoresis (1) or sucrose gradient centrifugation (2), two methods are described for the purification of the pigmented components from the photosynthetic membranes of the bacterium Chromatium purpuratum . All fractions were characterized by SDS‐polyacrylamide gel electrophoresis, electron microscopy and absorption spectroscopy. Method 2 gave pure core (the reaction center‐ light‐harvesting pigment‐protein complex 1) particles that had absorption maximum at 870 nm. Under electron microscopy they appeared as circles of 12–15 nm in diameter with protein density in the central (5–6 nm) and peripheral areas (9–15 nm), and as a trapezium of 4.5–5 nm in height with two layers of protein density and 10–12 nm and 13–15 nm bases. A model of photoreceptor units from C. purpuratum is suggested and discussed.