Difference between revisions of "Part:BBa K566023"

Revision as of 01:18, 29 September 2011

pcyA gene (constitutive expression)

pcyA (Phycocyanobilin:ferredoxin oxidoreductase) transcribed from constitutive promoter.

Gene in charge of the cromophore synthesis along with ho1 in Synechocystis which converts heme into PCB via a two-step oxidation/reduction process.

Usage and Biology

Is the best characterized member of the ferredoxin-dependent bilin reductase family. Unlike other ferredoxin-dependent bilin reductases that catalyze a two-electron reduction, PcyA sequentially reduces D-ring (exo) and A-ring (endo) vinyl groups of biliverdin IXalpha (BV) to yield phycocyanobilin, a key pigment precursor of the light-harvesting antennae complexes of red algae, cyanobacteria, and cryptophytes.

FIGURE 1.Reactions catalyzed by PcyA. A, PcyA reduces BV to 3Z/3E-PCB via an intermediate of 18EtBV in two steps. Two electrons per each step are supplied from ferredoxin. B, when BV13, an isomer of BV, is used as the substrate, PcyA reduces it to 3Z/3E-iso-PΦB using two electrons. Figure taken from Fukuyama K. et al (2010) J Biol Chem. 2010 January 8; 285(2): 1000–1007.

Sequence and Features