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Crystallization of the photosystem I reaction centre
Author(s) -
Ford Robert C.,
Picot Daniel,
Garavito R. Michael
Publication year - 1987
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1987.tb02403.x
Subject(s) - biology , crystallization , photosystem ii , computational biology , biophysics , photosynthesis , botany , chemical engineering , engineering
The reaction centre of the photosynthetic membrane complex photosystem I (PSI) from the thermophilic cyanobacterium Phormidium laminosum was found to crystallize under a range of conditions. The crystallization method, which can occur in the presence of larger detergent molecules than those used previously for the crystallization of membrane proteins, is presented in this report. Several crystal forms have been observed, and some of these show birefringence and linear dichroism. Optical measurements on crystals thicker than ˜5 µm were severely restricted because of the very high chlorophyll density within the crystals, but linear dichroism measurements on thin single crystals were possible and the results are presented here. By comparing the data with earlier measurements on oriented PSI complexes, a working model for the orientation of the PSI complexes within the crystal could be proposed. The PSI reaction centre is one of the largest and most complex membrane protein units that have been crystallized to date.