ABSTRACT
PS I in oxygenic systems at 4 À structure has become clearer relatively recently (Krauss et a l , 1996). Also, Jordan et a l , (2001) have determined the 3-dimensional structure of photosystem I in the cyanobacterium, Synechococcus elongatus at 2.5 Â resolution (Kuhlbrandt, 2001). This study has provided the atomic detail of protein subunits and cofactors of photosystem I.
