Reaction: bacteriochlorophyll a + 3 NADP+ = geranylgeranyl bacteriochlorophyllide a + 3 NADPH + 3 H+
Other name(s): bchP (gene name)
Systematic name: bacteriochlorophyll a:NADP+ oxidoreductase (geranylgeranyl-reducing)
Comments: The enzyme catalyses the successive reduction of the geranylgeraniol esterifying group to phytol, reducing three out of four double bonds, and transforming geranylgeranyl bacteriochlorophyllide a via dihydrogeranylgeranyl bacteriochlorophyllide a and tetrahydrogeranylgeranyl bacteriochlorophyllide a to bacteriochlorophyll a. The enzyme can also accept the pheophytin derivative geranylgeranyl bacteriopheophytin, converting it to bacteriopheophytin a.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
References:
1. Bollivar, D.W., Wang, S., Allen, J.P. and Bauer, C.E. Molecular genetic analysis of terminal steps in bacteriochlorophyll a biosynthesis: characterization of a Rhodobacter capsulatus strain that synthesizes geranylgeraniol-esterified bacteriochlorophyll a, Biochemistry 33 (1994) 12763-12768. [PMID: 7947681]
2. Addlesee, H.A. and Hunter, C.N. Physical mapping and functional assignment of the geranylgeranyl-bacteriochlorophyll reductase gene, bchP, of Rhodobacter sphaeroides, J. Bacteriol. 181 (1999) 7248-7255. [PMID: 10572128]
3. Addlesee, H.A. and Hunter, C.N. Rhodospirillum rubrum possesses a variant of the bchP gene, encoding geranylgeranyl-bacteriopheophytin reductase. J. Bacteriol. 184 (2002) 1578-1586. [PMID: 11872709]
4. Harada, J., Miyago, S., Mizoguchi, T., Azai, C., Inoue, K., Tamiaki, H. and Oh-oka, H. Accumulation of chlorophyllous pigments esterified with the geranylgeranyl group and photosynthetic competence in the CT2256-deleted mutant of the green sulfur bacterium Chlorobium tepidum, Photochem Photobiol Sci 7 (2008) 1179-1187. [PMID: 18846281]