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The light‐harvesting core‐complex and the B820‐subunit from Rhodopseudomonas marina . Part II. Electron microscopic characterisation
Author(s) -
Meckenstock Rainer U.,
Krusche Katarina,
Brunisholz René A.,
Zuber Herbert
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)81384-x
Subject(s) - photosynthetic reaction centre , vesicle , electron micrographs , crystallography , membrane , protein subunit , ring (chemistry) , hexagonal crystal system , chemistry , hexagonal lattice , crystal structure , photosynthesis , electron microscope , physics , optics , biochemistry , organic chemistry , antiferromagnetism , gene , condensed matter physics
Electron micrographs of photosynthetic membranes of the BChla‐containing bacterium Rp, marina showed a quasi‐crystalline structure. The photoreceptor units are arranged in a hexagonal lattice with a reaction center to reaction center distance of 102± Å. Purified B880‐complex was concentrated up to an OD ? of 60 which induced the formation of large protein vesicles. The protein complexes within these vesicles were highly ordered and showed a hexagonal lattice with the same center to center distance of 102±3 Å as was observed in the native membranes. Image processing of the micrographs revealed a ring‐like structure of the B880‐complex at 26 Å resolution and suggests that the B880‐complex consists of 5 or 6 subunits. For the first time it can be shown that an isolated core‐complex is in a stable, ring‐like structure even without the reaction center which is supposed to be located in the middle of the B880‐ring. The data indicate that the isolated B880‐complex exhibits the same structure as in the native membrane.