overview on chlorophylls and quinones in the photosystem I-type reaction centers

• Published in: Photosynthesis research Vol. 104; no. 2-3; pp. 305 - 319
• Main Authors: Ohashi, Shunsuke, Iemura, Tatsuya, Okada, Naoki, Itoh, Shingo, Furukawa, Hayato, Okuda, Masaaki, Ohnishi-Kameyama, Mayumi, Ogawa, Takuro, Miyashita, Hideaki, Watanabe, Tadashi, Itoh, Shigeru, Oh-oka, Hirozo, Inoue, Kazuhito, Kobayashi, Masami
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01.06.2010; Springer Netherlands; Springer; Springer Nature B.V
• Subjects: Bacteria; Bacteria - metabolism; Bacteriochlorophyll g; Biochemistry; Biomedical and Life Sciences; Chlorophyll; Chlorophyll - chemistry; Chlorophyll a; Dimerization; Electrons; Green sulfur bacteria; Heliobacterium group; Life Sciences; Menaquinone; Molecular structure; Photosynthesis; photosystem I; Photosystem I Protein Complex - chemistry; Phytochemistry; Plant Genetics and Genomics; Plant Physiology; Plant Sciences; Quinone; Quinones - chemistry; Review; Sulfur compounds; Photosystem I; Chlorophyll; Heliobacteria; Bacteriochlorophyll; Green sulfur bacteria; Menaquinone
• ISSN: 0166-8595; 1573-5079
• DOI: 10.1007/s11120-010-9530-3

Minor but key chlorophylls (Chls) and quinones in photosystem (PS) I-type reaction centers (RCs) are overviewed in regard to their molecular structures. In the PS I-type RCs, the prime-type chlorophylls, namely, bacteriochlorophyll (BChl) a′ in green sulfur bacteria, BChl g′ in heliobacteria, Chl a′ in Chl a-type PS I, and Chl d′ in Chl d-type PS I, function as the special pairs, either as homodimers, (BChl a′)₂ and (BChl g′)₂ in anoxygenic organisms, or heterodimers, Chl a/a′ and Chl d/d′ in oxygenic photosynthesis. Conversions of BChl g to Chl a and Chl a to Chl d take place spontaneously under mild condition in vitro. The primary electron acceptors, A ₀, are Chl a-derivatives even in anoxygenic PS I-type RCs. The secondary electron acceptors are naphthoquinones, whereas the side chains may have been modified after the birth of cyanobacteria, leading to succession from menaquinone to phylloquinone in oxygenic PS I.