Premium
Molecular aspects of photosystem I
Author(s) -
Scheller Henrik Vibe,
Naver Helle,
Møller Birger Lindberg
Publication year - 1997
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1997.tb00010.x
Subject(s) - photosystem i , protein subunit , electron transport chain , photosystem ii , iron–sulfur cluster , chloroplast , sulfur , electron acceptor , photosynthetic reaction centre , chlorophyll a , cyanobacteria , chemistry , chlorophyll , cofactor , acceptor , photosynthesis , biochemistry , biology , bacteria , botany , enzyme , gene , physics , genetics , organic chemistry , condensed matter physics
Photosystem I (PSI) in higher plants consists of 17 polypeptide subunits. Cofactors are chlorophyll a and b , β‐carotene, phylloquinone and iron‐sulfur clusters. Eight subunits are specific for higher plants while the remaining ones are also present in cyanobacteria. Two 80‐kDa subunits (PSI‐A and ‐B) constitute the major part of PSI and bind most of the pigments and electron donors and acceptors. The 9‐kDa PSI‐C carries the remaining electron acceptors which are [4Fe‐4S] iron sulfur clusters. PSI‐D, ‐E and ‐H have importance for integrity and function at the stromal face of PSI while PSI‐F has importance for function at the lumenal face. PSI‐N is localized at the lumenal side, but its function is unknown. Four subunits are light‐harvesting chlorophyll a/b ‐binding proteins. The remaining subunits are integral membrane proteins with poorly understood function. Subunit interactions have been studied in reconstitution experiments and by cross‐linking studies. Based on these data, it is concluded that iron‐sulfur cluster F B is proximal to F X and that F A is the terminal acceptor in PSI. Similarities between PSI and the reaction center from green sulfur bacteria are discussed.