View source for 2iup

[[Image:2iup.gif|left|200px]]<br />
<applet load="2iup" size="450" color="white" frame="true" align="right" spinBox="true" 
caption="2iup, resolution 1.80&Aring;" />
'''CRYSTAL STRUCTURE OF DITHIONITE-REDUCED AROMATIC AMINE DEHYDROGENASE (AADH) FROM ALCALIGENES FAECALIS'''<br />

==Overview==
The quinoprotein aromatic amine dehydrogenase (AADH) uses a covalently, bound tryptophan tryptophylquinone (TTQ) cofactor to oxidatively deaminate, primary aromatic amines. Recent crystal structures have provided insight, into the reductive half-reaction. In contrast, no atomic details are, available for the oxidative half-reaction. The TTQ O7 hydroxyl group is, protonated during reduction, but it is unclear how this proton can be, removed during the oxidative half-reaction. Furthermore, compared with the, electron transfer from the N-quinol form, electron transfer from the, non-physiological O-quinol form to azurin is significantly slower. Here we, report crystal structures of the O-quinol, N-quinol, and N-semiquinone, forms of AADH. A comparison of oxidized and substrate reduced AADH species, reveals changes in the TTQ-containing subunit, extending from residues in, the immediate vicinity of the N-quinol to the putative azurin docking, site, suggesting a mechanism whereby TTQ redox state influences, interprotein electron transfer. In contrast, chemical reduction of the TTQ, center has no significant effect on protein conformation. Furthermore, structural reorganization upon substrate reduction places a water molecule, near TTQ O7 where it can act as proton acceptor. The structure of the, N-semiquinone, however, is essentially similar to oxidized AADH., Surprisingly, in the presence of substrate a covalent N-semiquinone, substrate adduct is observed. To our knowledge this is the first detailed, insight into a complex, branching mechanism of quinone oxidation where, significant structural reorganization upon reduction of the quinone center, directly influences formation of the electron transfer complex and nature, of the electron transfer process.

==About this Structure==
2IUP is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Alcaligenes_faecalis Alcaligenes faecalis]. Active as [http://en.wikipedia.org/wiki/Aralkylamine_dehydrogenase Aralkylamine dehydrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.4.99.4 1.4.99.4] Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2IUP OCA]. 

==Reference==
Atomic level insight into the oxidative half-reaction of aromatic amine dehydrogenase., Roujeinikova A, Scrutton NS, Leys D, J Biol Chem. 2006 Dec 29;281(52):40264-72. Epub 2006 Sep 27. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=17005560 17005560]
[[Category: Alcaligenes faecalis]]
[[Category: Aralkylamine dehydrogenase]]
[[Category: Single protein]]
[[Category: Leys, D.]]
[[Category: Roujeinikova, A.]]
[[Category: Scrutton, N.]]
[[Category: oxidoreductase]]

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