A Second Nitrogenase-like Enzyme for Bacteriochlorophyll Biosynthesis

2006/03/30 by Jiro Nomata, Tadashi Mizoguchi, Hitoshi Tamiaki +1 · 23 citations
Biochemistry, Genetics and Molecular Biology · Energy · Environmental Science · #Photosynthetic Processes and Mechanisms #Algal biology and biofuel production #Microbial Community Ecology and Physiology

paper · doi:10.1074/jbc.m601750200

Abstract

In most photosynthetic organisms, the chlorin ring structure of chlorophyll a is formed by the reduction of the porphyrin D-ring by the dark-operative nitrogenase-like enzyme, protochlorophyllide reductase (DPOR). Subsequently, the chlorin B-ring is reduced in bacteriochlorophyll biosynthesis to form a bacteriochlorin ring structure. Phenotypic analysis of mutants lacking one of three genes, bchX, bchY, or bchZ, which show significant sequence similarity to the structural genes of nitrogenase, suggests that a second nitrogenase-like enzyme is involved in the chlorin B-ring reduction. However, there is no biochemical evidence for this. Here, we report the reconstitution of chlorophyllide a reductase (COR) with purified proteins. Two Rhodobacter capsulatus strains that overexpressed Strep-tagged BchX and BchY were isolated. Strep-tagged BchX was purified as a single polypeptide, and BchZ was co-purified with Strep-tagged BchY. When BchX and BchY-BchZ components were incubated with chlorophyllide a, ATP, and dithionite under anaerobic conditions, chlorophyllide a was converted to a new pigment with a Qy band of longer wavelength at 734 nm (P734) in 80% acetone. The formation of P734 was dependent on ATP and dithionite. High performance liquid chromatography and mass spectroscopic analysis indicated that P734 is 3-vinyl bacteriochlorophyllide a, which is formed by the B-ring reduction of chlorophyllide a. These results demonstrate that the B-ring of chlorin is reduced by a second nitrogenase-like enzyme and that the sequential actions of two nitrogenase-like enzymes, DPOR and COR, convert porphyrin to bacteriochlorin. The evolutionary implications of nitrogenase-like enzymes to determine the ring structure of (bacterio)chlorophyll pigments are discussed.

Cited by

• Crystal Structure of the Nitrogenase-like Dark Operative Protochlorophyllide Oxidoreductase Catalytic Complex (ChlN/ChlB)2
• Regulatory and retrograde signaling networks in the chlorophyll biosynthetic pathway
• Evolution of light-independent protochlorophyllide oxidoreductase
• The tetrapyrrole biosynthetic pathway and its regulation in Rhodobacter capsulatus. [europepmc]
• Crystal structure of the nitrogenase-like dark operative protochlorophyllide oxidoreductase catalytic complex (ChlN/ChlB)2. [europepmc]
• P+ state of nitrogenase p-cluster exhibits electronic structure of a [Fe4S4]+ cluster. [europepmc]
• An unexpectedly branched biosynthetic pathway for bacteriochlorophyll b capable of absorbing near-infrared light. [europepmc]
• A novel "oxygen-induced" greening process in a cyanobacterial mutant lacking the transcriptional activator ChlR involved in low-oxygen adaptation of tetrapyrrole biosynthesis. [europepmc]
• Nitrogenase and homologs. [europepmc]
• Diazotroph Community Characterization via a High-Throughput nifH Amplicon Sequencing and Analysis Pipeline. [europepmc]
• Inhibition of bacteriochlorophyll biosynthesis in the purple phototrophic bacteria Rhodospirillumrubrum and Rhodobacter capsulatus grown in the presence of a toxic concentration of selenite. [europepmc]
• Diazotroph Diversity and Nitrogen Fixation in Summer Active Perennial Grasses in a Mediterranean Region Agricultural Soil. [europepmc]
• Biosynthesis of the modified tetrapyrroles-the pigments of life. [europepmc]
• Substrate recognition induces sequential electron transfer across subunits in the nitrogenase-like DPOR complex. [europepmc]
• In situ formation of photoactive B-ring reduced chlorophyll isomer in photosynthetic protein LH2. [europepmc]
• Incomplete Hydrogenation by Geranylgeranyl Reductase from a Proteobacterial Phototroph Halorhodospira halochloris, Resulting in the Production of Bacteriochlorophyll with a Tetrahydrogeranylgeranyl Tail. [europepmc]
• Genomic Features of the Bundle-Forming Heliobacterium Heliophilum fasciatum . [europepmc]
• The Photoactive Photosynthetic Reaction Center of a Rhodobacter sphaeroides Mutant Lacking 3-Vinyl (Bacterio)Chlorophyllide a Hydratase Contains 3-Vinyl Bacteriochlorophyll a . [europepmc]
• A Rhizobium bacterium and its population dynamics under different culture conditions of its associated toxic dinoflagellate Gambierdiscus balechii . [europepmc]
• Engineering Chlorophyll, Bacteriochlorophyll, and Carotenoid Biosynthetic Pathways in Escherichia coli . [europepmc]
• Illuminating the coevolution of photosynthesis and Bacteria. [europepmc]
• A nitrogenase-like enzyme is involved in the novel anaerobic assimilation pathway of a sulfonate, isethionate, in the photosynthetic bacterium Rhodobacter capsulatus . [europepmc]
• Nitrogen Fixation Associated with Microcystis Colonies Promotes Harmful Cyanobacterial Blooms across North American Lakes. [europepmc]

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• Regulation of nitrogenase in the photosynthetic bacteriumRhodobacter sphaeroidescontainingdraTGandnifHDKgenes fromRhodobacter capsulatus
• Regulatory and retrograde signaling networks in the chlorophyll biosynthetic pathway
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