HO1 and PcyA proteins involved in phycobilin biosynthesis form a 1:2 complex with ferredoxin-1 required for photosynthesis

Abstract 

The HO1 and PcyA genes, encoding heme oxygenase-1 (HO1) and phycocyanobilin (PCB):ferredoxin (Fd) oxidoreductase (PcyA), respectively, are required for chromophore synthesis in photosynthetic light-harvesting complexes, photoreceptors, and circadian clocks. In the PCB biosynthetic pathway, heme first undergoes cleavage to form biliverdin. I confirmed that Fd1 induced the formation of a stable and functional HO1 complex by the gel mobility shift assay. Furthermore, analysis by a chemical cross-linking technique designed to detect protein-protein interactions revealed that HO1 and PcyA directly interact with Fd in a 1:2 ratio. Thus, Fd1, a one-electron carrier protein in photosynthesis, drives the phycobilin biosynthetic pathway.

Structured summary

MINT-7014657: Fd1 (uniprotkb:P0A3C9) and HO1 (uniprotkb:Q8DLW1) bind (MI:0407) by comigration in non-denaturing gel electrophoresis (MI:0404)

MINT-7014666: HO1 (uniprotkb:Q8DLW1 and Fd1 (uniprotkb:P0A3C9) bind (MI:0407) by cross-linking studies (MI:0030)

MINT-7014675: PcyA (uniprotkb:P59288) and Fd1 (uniprotkb:P0A3C9) bind (MI:0407) by cross-linking studies (MI:0030)

Abbreviations: HO, heme oxygenase, PCB, phycocyanobilin, Fd, ferredoxin, PcyA, phycocyanobilin:ferredoxin oxidoreductase, BV, biliverdin, BVR, biliverdin reductase, CO, carbon monoxide, Te, Thermosynechococcus elongatus BP-1, LB, Luria–Bertani, PCR, polymerase chain reaction, β-ME, β-mercaptoethanol, FNR, ferredoxin-NADP⁺ oxidoreductase, PAGE, polyacrylamide gel electrophoresis, NADPH, reduced nicotinamide adenine dinucleotide phosphate, G6P, glucose-6-phosphate, G6PDH, glucose-6-phosphate dehydrogenase, BS³, bis-(sulfosuccinimidyl) suberate, SDS, sodium dodecyl sulfate, HPLC, high-performance liquid chromatography

Keywords: Phycobilin biosynthesis, Ferredoxin-dependent enzyme, Heme oxygenase, Phycocyanobilin:ferredoxin oxidoreductase, 1:2 Complex, Gel mobility shift assay