Reaction: D-sedoheptulose 7-phosphate = demethyl-4-deoxygadusol + phosphate + H2O
For diagram of reaction click here.
Glossary: demethyl-4-deoxygadusol = 2,3,5-trihydroxy-5-(hydroxymethyl)cyclohex-2-en-1-one
Other name(s): Nos2 (gene name); Anb2 (gene name)
Systematic name: D-sedoheptulose-7-phosphate phosphate-lyase (cyclizing; demethyl-4-deoxygadusol-forming)
Comments: The enzyme, characterized from the cyanobacterium Nostoc punctiforme PCC 73102, is involved in the biosynthesis of the sunscreen compound shinorine. It requires a divalent metal ion (Zn2+ or Co2+) and an NAD+ cofactor, which is transiently reduced during the reaction. cf. EC 4.2.3.152, 2-epi-5-epi-valiolone synthase and EC 4.2.3.155, 2-epi-valiolone synthase.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number:
References:
1. Balskus, E.P. and Walsh, C.T. The genetic and molecular basis for sunscreen biosynthesis in cyanobacteria. Science 329 (2010) 1653-1656. [PMID: 20813918]
2. Asamizu, S., Xie, P., Brumsted, C.J., Flatt, P.M. and Mahmud, T. Evolutionary divergence of sedoheptulose 7-phosphate cyclases leads to several distinct cyclic products. J. Am. Chem. Soc. 134 (2012) 12219-12229. [PMID: 22741921]