3PQB

The crystal structure of pregilvocarcin in complex with GilR, an oxidoreductase that catalyzes the terminal step of gilvocarcin biosynthesis

Summary for 3PQB

• Entry DOI: 10.2210/pdb3pqb/pdb
• Related: 3POP
• Descriptor: Putative oxidoreductase, FLAVIN-ADENINE DINUCLEOTIDE, (1R)-1,4-anhydro-6-deoxy-1-[(6R)-8-ethenyl-1,6-dihydroxy-10,12-dimethoxy-6H-dibenzo[c,h]chromen-4-yl]-D-galactitol, ... (4 entities in total)
• Functional Keywords: oxidoreductase, fad binding protein, covalently bound fad
• Biological source: Streptomyces griseoflavus
• Total number of polymer chains: 4
• Total formula weight: 222778.60

Authors

Noinaj, N.,Bosserman, M.A.,Schickli, M.A.,Kharel, M.K.,Rohr, J.,Buchanan, S.K. (deposition date: 2010-11-25, release date: 2011-05-11, Last modification date: 2024-11-06)

Primary citation

Noinaj, N.,Bosserman, M.A.,Schickli, M.A.,Piszczek, G.,Kharel, M.K.,Pahari, P.,Buchanan, S.K.,Rohr, J.
The Crystal Structure and Mechanism of an Unusual Oxidoreductase, GilR, Involved in Gilvocarcin V Biosynthesis.
J.Biol.Chem., 286:23533-23543, 2011

PubMed Abstract: GilR is a recently identified oxidoreductase that catalyzes the terminal step of gilvocarcin V biosynthesis and is a unique enzyme that establishes the lactone core of the polyketide-derived gilvocarcin chromophore. Gilvocarcin-type compounds form a small distinct family of anticancer agents that are involved in both photo-activated DNA-alkylation and histone H3 cross-linking. High resolution crystal structures of apoGilR and GilR in complex with its substrate pregilvocarcin V reveals that GilR belongs to the small group of a relatively new type of the vanillyl-alcohol oxidase flavoprotein family characterized by bicovalently tethered cofactors. GilR was found as a dimer, with the bicovalently attached FAD cofactor mediated through His-65 and Cys-125. Subsequent mutagenesis and functional assays indicate that Tyr-445 may be involved in reaction catalysis and in mediating the covalent attachment of FAD, whereas Tyr-448 serves as an essential residue initiating the catalysis by swinging away from the active site to accommodate binding of the 6R-configured substrate and consequently abstracting the proton of the hydroxyl residue of the substrate hemiacetal 6-OH group. These studies lay the groundwork for future enzyme engineering to broaden the substrate specificity of this bottleneck enzyme of the gilvocarcin biosynthetic pathway for the development of novel anti-cancer therapeutics.

PubMed: 21561854
DOI: 10.1074/jbc.M111.247833

Experimental method

X-RAY DIFFRACTION (2.324 Å)