View source for 2igm

[[Image:2igm.gif|left|200px]]<br /><applet load="2igm" size="350" color="white" frame="true" align="right" spinBox="true" 
caption="2igm, resolution 1.90&Aring;" />
'''Crystal structure of recombinant pyranose 2-oxidase H548N mutant'''<br />

==Overview==
Pyranose 2-oxidase (P2Ox) participates in fungal lignin degradation by producing the H2O2 needed for lignin-degrading peroxidases. The enzyme oxidizes cellulose- and hemicellulose-derived aldopyranoses at C2 preferentially, but also on C3, to the corresponding ketoaldoses. To investigate the structural determinants of catalysis, covalent flavinylation, substrate binding, and regioselectivity, wild-type and mutant P2Ox enzymes were produced and characterized biochemically and structurally. Removal of the histidyl-FAD linkage resulted in a catalytically competent enzyme containing tightly, but noncovalently bound FAD. This mutant (H167A) is characterized by a 5-fold lower kcat, and a 35-mV lower redox potential, although no significant structural changes were seen in its crystal structure. In previous structures of P2Ox, the substrate loop (residues 452-457) covering the active site has been either disordered or in a conformation incompatible with carbohydrate binding. We present here the crystal structure of H167A in complex with a slow substrate, 2-fluoro-2-deoxy-D-glucose. Based on the details of 2-fluoro-2-deoxy-D-glucose binding in position for oxidation at C3, we also outline a probable binding mode for D-glucose positioned for regioselective oxidation at C2. The tentative determinant for discriminating between the two binding modes is the position of the O6 hydroxyl group, which in the C2-oxidation mode can make favorable interactions with Asp452 in the substrate loop and, possibly, a nearby arginine residue (Arg472). We also substantiate our hypothesis with steady-state kinetics data for the alanine replacements of Asp452 and Arg472 as well as the double alanine 452/472 mutant.

==About this Structure==
2IGM is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Trametes_ochracea Trametes ochracea] with <scene name='pdbligand=FAD:'>FAD</scene> and <scene name='pdbligand=MES:'>MES</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Pyranose_oxidase Pyranose oxidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.1.3.10 1.1.3.10] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2IGM OCA]. 

==Reference==
Structural basis for substrate binding and regioselective oxidation of monosaccharides at C3 by pyranose 2-oxidase., Kujawa M, Ebner H, Leitner C, Hallberg BM, Prongjit M, Sucharitakul J, Ludwig R, Rudsander U, Peterbauer C, Chaiyen P, Haltrich D, Divne C, J Biol Chem. 2006 Nov 17;281(46):35104-15. Epub 2006 Sep 19. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=16984920 16984920]
[[Category: Pyranose oxidase]]
[[Category: Single protein]]
[[Category: Trametes ochracea]]
[[Category: Divne, C.]]
[[Category: FAD]]
[[Category: MES]]
[[Category: 8-alpha-(n3) histidyl flavinylation]]
[[Category: active-site mutant]]
[[Category: gmc oxidoreductase]]
[[Category: h548n]]
[[Category: homotetramer]]
[[Category: oxidoreductase]]
[[Category: phbh fold]]
[[Category: rossman fold]]

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