THE 8.5-ANGSTROM PROJECTION MAP OF THE LIGHT-HARVESTING COMPLEX-I FROM RHODOSPIRILLUM-RUBRUM REVEALS A RING COMPOSED OF 16 SUBUNITS

被引:554
作者
KARRASCH, S
BULLOUGH, PA
GHOSH, R
机构
[1] MRC,MOLEC BIOL LAB,CAMBRIDGE CB2 2QH,ENGLAND
[2] UNIV BASEL,BIOZENTRUM,DEPT MICROBIOL,CH-4056 BASEL,SWITZERLAND
关键词
ELECTRON CRYOMICROSCOPY; LHC I; PHOTOSYNTHESIS; RHODOSPIRILLUM RUBRUM; 2-D CRYSTALS;
D O I
10.1002/j.1460-2075.1995.tb07041.x
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Two-dimensional crystals from light-harvesting complex I (LHC I) of the purple non-sulfur bacterium Rhodospirillum rubrum have been reconstituted from detergent-solubilized protein complexes. Frozen-hydrated samples have been analysed by electron microscopy. The crystals diffract beyond 8 Angstrom and a projection map was calculated to 8.5 Angstrom. The projection map shows 16 subunits in a 116 Angstrom diameter ring with a 68 Angstrom hole in the centre, These dimensions are sufficient to incorporate a reaction centre in vivo. Within each subunit, density for the alpha- and the beta-polypeptide chains is clearly resolved, and the density for the bacteriochlorophylls can be assigned. The experimentally determined structure contradicts models of the LHC I presented so far.
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页码:631 / 638
页数:8
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