Quinoproteins form a class of dehydrogenases distinct from the NAD(P)- and flavin-dependent enzymes, using one of four different quinone cofactors for the oxidation of a variety of compounds. Soluble glucose dehydrogenase (s-GDH) from the bacterium Acinetobacter calcoaceticus is a quinoprotein that requires the cofactor pyrroloquinoline quinone (PQQ) to catalyse the oxidation of glucose to gluconolactone [1]. s-GDH has six 4-stranded beta-sheets in a beta-propeller fold.
Oubrie A, Rozeboom HJ, Kalk KH, Duine JA, Dijkstra BW.
The 1.7 A crystal structure of the apo form of the soluble quinoprotein glucose dehydrogenase from Acinetobacter calcoaceticus reveals a novel internal conserved sequence repeat.
J. Mol. Biol. 289 1999 319-33
[PubMed: 10366508] http://dx.doi.org/10.1006/jmbi.1999.2766