PMID:8158642

Citation	Bollivar, DW, Suzuki, JY, Beatty, JT, Dobrowolski, JM and Bauer, CE (1994) Directed mutational analysis of bacteriochlorophyll a biosynthesis in Rhodobacter capsulatus. J. Mol. Biol. 237:622-40
Abstract	Previous studies have established that most if not all of the genes required for synthesis of the Rhodobacter capsulatus essential photosystem are clustered on a 46 kb region of the chromosome known as the photosynthesis gene cluster. This region has recently been sequenced in its entirety by Hearst and co-workers, revealing the existence of 23 open reading frames, many of which are thought to be involved in the synthesis of bacteriochlorophyll. In this study we have undertaken a systematic directed mutational analysis of 12 open reading frames in the photosynthesis gene cluster to evaluate whether individual open reading frames have a role in photopigment biosynthesis. The results of this analysis demonstrate that mutations constructed in seven open reading frames resulted in a loss of bacteriochlorophyll biosynthesis, concomitant with the accumulation of specific intermediates in the Mg-tetrapyrrole biosynthetic pathway. One mutation was observed to result in partial disruption of bacteriochlorophyll biosynthesis, leading to the accumulation of bacteriochlorophyll as well as an intermediate in the biosynthetic pathway. We also observed that disruptions constructed in four open reading frames had no discernible effect on the synthesis of photopigments. The results of this analysis are discussed with regard to our current understanding of the role of each of these open reading frames in the synthesis of the R. capsulatus photosystem.
Links	PubMed Online version:10.1006/jmbi.1994.1260
Keywords	Bacterial Proteins/analysis; Bacterial Proteins/biosynthesis; Bacterial Proteins/genetics; Chromatography, High Pressure Liquid; DNA Mutational Analysis; Genes, Bacterial; Light-Harvesting Protein Complexes; Molecular Sequence Data; Multigene Family; Mutagenesis, Insertional; Open Reading Frames/genetics; Photosynthetic Reaction Center Complex Proteins/genetics; Pigments, Biological/analysis; Pyrroles/analysis; Rhodobacter capsulatus/genetics; Rhodobacter capsulatus/metabolism; Tetrapyrroles
edit table

Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
RHOCB:BCHE	involved_in	GO:0030494: bacteriochlorophyll biosynthetic process	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
RHOCB:BCHE		GO:0030494: bacteriochlorophyll biosynthetic process	ECO:0000315:		P		Table 3: Pigment extracts of strain D13575 (bchE mutant) exhibited an absorbance peak at 590 nm, which is charaeteristic of Mg-protoporphyrin monomthylester accumulation.	complete CACAO 3071
RHOCA:BCHM	involved_in	GO:0030494: bacteriochlorophyll biosynthetic process	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
RHOCA:BCHM		GO:0030494: bacteriochlorophyll biosynthetic process	ECO:0000315:		P		The Mg-tetrapyrroles accumulated by the bchM disrupted strain ZY4 were examined using an excitation wavelength of 430 nm. The results of this analysis demonstrate that ZY4 did indeed accumulate Mg-protoporphyrin monomethylester as indicated by fluorescence em ission peaks at 595nm and 630 nm (Figure 3A).	complete CACAO 3072
RHOCB:BCHJ	involved_in	GO:0030494: bacteriochlorophyll biosynthetic process	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
RHOCB:BCHJ		GO:0030494: bacteriochlorophyll biosynthetic process	ECO:0000315:		P		Mutational analyses revealed that ORF213 (bchJ) appears to be involved in reduction of the 4-vinyl group. Strain DB213 (which contains a disruption of ORF213) excretes a pigment with an absorbance maximum at 627 nm in acetone/methanol (Figure 5), which is indicative of monovinyl or divinyl protochlorophyllide.	complete CACAO 3073
RHOCB:BCHF	involved_in	GO:0030494: bacteriochlorophyll biosynthetic process	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
RHOCB:BCHF		GO:0030494: bacteriochlorophyll biosynthetic process	ECO:0000315:		P		Strain CB1200 was constructed, which contains a point mutation in the bchF gene as well as a directed disruption of the bchZ locus (Table 1). This strain failed to both hydroxylate the vinyl group on ring-A as well or reduce ring- B, thereby resulting in the accumulation of chlorophyllide a intermediate.	complete CACAO 3074

References

See Help:References for how to manage references in GONUTS.