Pyrroloquinoline-quinone synthase explained

Pyrroloquinoline-quinone synthase
Ec Number:	1.3.3.11

In enzymology, a pyrroloquinoline-quinone synthase is an enzyme that catalyzes the chemical reaction

6-(2-amino-2-carboxyethyl)-7,8-dioxo-1,2,3,4,5,6,7,8-octahydroquinoline-2,4-dicarboxylate + 3 O₂

\rightleftharpoons 4,5-dioxo-3a,4,5,6,7,8,9,9b-octahydro-1H-pyrrolo[2,3-f]quinoline- 2,7,9-tricarboxylate + 2 H₂O₂ + 2 H₂O

The two substrates of this enzyme are 6-(2-amino-2-carboxyethyl)-7,8-dioxo-1,2,3,4,5,6,7,8-octahydroquinoline-2,4-dicarboxylate, and O₂, whereas its 3 products are 4,5-dioxo-3a,4,5,6,7,8,9,9b-octahydro-1H-pyrrolo[2,3-f]quinoline-2,7,9-tricarboxylate, H₂O₂, and H₂O.

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-CH group of donor with oxygen as acceptor. The systematic name of this enzyme class is 6-(2-amino-2-carboxyethyl)-7,8-dioxo-1,2,3,4,5,6,7,8-octahydroquinol ine-2,4-dicarboxylate:oxygen oxidoreductase (cyclizing). This enzyme is also called PqqC.

References

• Magnusson OT, Toyama H, Saeki M, Schwarzenbacher R, Klinman JP . 2004 . The structure of a biosynthetic intermediate of pyrroloquinoline quinone (PQQ) and elucidation of the final step of PQQ biosynthesis . J. Am. Chem. Soc. . 126 . 5342 - 3 . 15113189 . 10.1021/ja0493852 . 17 .
• Klinman JP, Schwarzenbacher R . 2004 . Quinone biogenesis: Structure and mechanism of PqqC, the final catalyst in the production of pyrroloquinoline quinone . Proc. Natl. Acad. Sci. U.S.A. . 101 . 7913 - 8 . 15148379 . 10.1073/pnas.0402640101 . 21 . 419531 . free .
• Toyama H, Chistoserdova L, Lidstrom ME . Sequence analysis of pqq genes required for biosynthesis of pyrroloquinoline quinone in Methylobacterium extorquens AM1 and the purification of a biosynthetic intermediate . Microbiology . 1997 . 143 . 595 - 602 . 9043136 . 10.1099/00221287-143-2-595 . 2 . free .
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• RC . 2004 . Crystal structure of PqqC from Klebsiella pneumoniae at 2.1 A resolution . Proteins . 56 . 401 - 3 . 15211525 . 10.1002/prot.20085 . Stenner-Liewen . F . Liewen . H . Reed . JC . Liddington . RC . 2 . 11735291 . free .