EC Number   |
General Information |
Reference |
|---|
   1.3.7.4 | evolution |
enzyme structure analysis and comparison, overview. PPhiB synthase is a member of the ferredoxin-dependent bilin reductase (FDBR) family. The FDBR family comprises several different but closely related proteins including phycocyanobilin: ferredoxin oxidoreductase (PcyA, EC 1.3.7.5), 15,16-dihydrobiliverdin:ferredoxin oxidoreductase (PebA, EC 1.3.7.2), phycoerythrobilin:ferredoxin oxidoreductase (PebB, EC 1.3.7.3), phycoerythrobilin synthase (PebS, EC 1.3.7.6), and PPhiB synthase (EC 1.3.7.4). These enzymes are widely distributed in oxygenic phototrophs |
763272 |
| 1.3.7.4 | evolution |
phylogenetic analysis of CsHY2 homologues from different plants |
763754 |
| 1.3.7.4 | evolution |
synthesis of linear tetrapyrrole chromophores in cyanobacteria, algae, and plants, overview |
725252 |
| 1.3.7.4 | malfunction |
a recessive mutant, exhibiting highly enhanced submergence resistance, is identified. Phenotypical analyses show that this resistant to flooding (rf) mutant displays slightly chlorotic leaves and spontaneous initiation of adventitious roots (ARs) on stems. The mutation is mapped to the phytochromobilin synthase gene AUREA (AU), in which a single amino acid substitution from asparagine to tyrosine is found. Temporal coincidence of the two phenotypes is evidenced in the rf mutant: chlorosis and spontaneous AR formation, revealing that AU functions by maintaining heme homeostasis. Mutation of the AU gene appears to have minimal impact on tomato growth and fruit yield. The rf mutant is highly resistant to waterlogging in contrast to the wild-type, phenotypes, overview. Active HO-1 is necessary for the scion of rf to stimulate ARs in the stock of wild-type, but there is insufficient HO-1 in the wild-type hypocotyls to initiate AR primordium |
763128 |
| 1.3.7.4 | malfunction |
the long hypocotyl mutant C1238 is identified from an EMS-induced mutagenesis population of the cucumber inbred line CCMC with normal hypocotyl and green leaves. The mutant C1238 exhibits apparently elongated hypocotyl and yellow-green leaves at the seedling stage |
763754 |
| 1.3.7.4 | metabolism |
enzyme phytochromobilin synthase function in the heme pathway in tetrapyrrole metabolism, overview |
763128 |
| 1.3.7.4 | more |
the overall structure of tomato PPhiB synthase is similar to those of other ferredoxin-dependent bilin reductases (FDBRs), except for the addition of a long C-terminal loop and short helices. The C-terminal loop is part of the biliverdin-binding pocket and that two basic residues in the C-terminal loop form salt bridges with the propionate groups of biliverdin. The C-terminal loop is involved in the interaction with ferredoxin and biliverdin. The configuration of biliverdin bound to tomato PPhiB synthase differed from that of biliverdin ound to other FDBRs, and its orientation in PPhiB synthase is inverted relative to its orientation in the other FDBRs. Enzyme structure analysis and comparison, overview. Two aspartic acid residues, Asp123 and Asp263, form hydrogen bonds with water molecules and are essential for the site-specific A-ring reduction of biliverdin. Product release mechanism: PPhiB synthase-catalyzed stereospecific reduction produces 2(R)-PPhiB, which when bound to PPhiB synthase collides with the side chain of Val-121, releasing 2(R)-PPhiB from the synthase |
763272 |
| 1.3.7.4 | physiological function |
Hy2 mutants display a long hypocotyl in white light. Mutant seedlings grown under continuous far-red light display a typical blind phenotype showing very long hypocotyls and closed cotyledons. When grown in short-day regime, wild-type bolts after having produced about 44 leaves whereas the null mutants flower after 18 to 20 leaves |
743476 |
| 1.3.7.4 | physiological function |
HY2 synthesizes the open chain tetrapyrrole chromophore for light-sensing phytochromes. It catalyzes the double bond reduction of a heme-derived tetrapyrrole intermediate biliverdin IXalpha at the A-ring diene system |
712484 |
| 1.3.7.4 | physiological function |
in addition to the classic function of the enzyme phytochromobilin synthase (gene AUREA, AU), in phytochrome and chlorophyll biogenesis in leaves, a role in mediating adventitious roots (AR) formation on stems is uncovered. Genetic evidence for the involvement of the AU-heme oxygenase-1-heme pathway in AR initiation is found in tomato. Dual roles of phytochromobilin synthase in chlorophyll synthesis and AR primordia initiation, overview. Communication between leaves and hypocotyls is responsible for AR initiation |
763128 |
