COMPARED STRUCTURE OF PLANT AND BACTERIAL PHOTOSYNTHETIC REACTION CENTERS - EVOLUTIONARY IMPLICATIONS

The properties of reaction centers are compared in plants and in photosynthetic bacteria. The comparison emphasizes the QB (and herbicide) binding site in PS II and purple bacteria, and the sequence of electron acceptors in PS I and green sulfur bacteria. Evolutionary implications are discussed, with the point of view that reaction centers of the purple bacterial type are more ancient and that centers with low-potential acceptors (green sulfur bacteria, Gram-positive bacteria, PS I) have developed more recently. © 1990.