6wpu

<table><tr><td colspan='2'>[[6wpu]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Allsa Allsa]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6WPU OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=6WPU FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=FAD:FLAVIN-ADENINE+DINUCLEOTIDE'>FAD</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">AsFMO1 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=4682 ALLSA])</td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=6wpu FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6wpu OCA], [http://pdbe.org/6wpu PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6wpu RCSB], [http://www.ebi.ac.uk/pdbsum/6wpu PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6wpu ProSAT]</span></td></tr>

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== Publication Abstract from PubMed ==

Allicin is a component of the characteristic smell and flavor of garlic (Allium sativum). A flavin-containing monooxygenase (FMO) produced by A. sativum (AsFMO) was previously proposed to oxidize S-allyl-L-cysteine (SAC) to alliin, an allicin precursor. Here, we present a kinetic and structural characterization of AsFMO that suggests a possible contradiction to this proposal. Results of steady-state kinetic analyses revealed that AsFMO exhibits negligible activity with SAC; however, the enzyme was highly active with L-cysteine, N-acetyl-L-cysteine, and allyl mercaptan. We found that allyl mercaptan with NADPH is the preferred substrate-cofactor combination. Rapid-reaction kinetic analyses showed that NADPH binds tightly (KD ~2 muM) to AsFMO and that the hydride transfer occurs with pro-R stereospecificity. We detected formation of a long-wavelength band when AsFMO was reduced by NADPH, probably representing the formation of a charge transfer complex. In the absence of substrate, the reduced enzyme, in complex with NADP+, reacted with oxygen and formed an intermediate with a spectrum characteristic of C4a-hydroperoxyflavin, which decays several orders of magnitude slower than the kcat. The presence of substrate enhanced C4a-hydroperoxyflavin formation, and upon hydroxylation, oxidation occurred at a rate constant similar to the kcat. The structure of AsFMO complexed with FAD at 2.08 A resolution features two domains for binding of FAD and NADPH, representative of class B flavin monooxygenases. These biochemical and structural results are consistent with AsFMO being an S-monooxygenase involved in allicin biosynthesis by direct formation of sulfenic acid, and not by SAC oxidation.

 

== References ==

[[Category: Allsa]]

[[Category: Campbell, A C]]

[[Category: Schuermann, J P]]

[[Category: Tanner, J J]]

[[Category: Oxidoreductase]]