2gmh

[[Image:2gmh.gif|left|200px]]<br /><applet load="2gmh" size="350" color="white" frame="true" align="right" spinBox="true"

caption="2gmh, resolution 2.50&Aring;" />

'''Structure of Porcine Electron Transfer Flavoprotein-Ubiquinone Oxidoreductase in Complexed with Ubiquinone'''<br />

==Overview==

Electron transfer flavoprotein-ubiquinone oxidoreductase (ETF-QO) is a 4Fe4S flavoprotein located in the inner mitochondrial membrane. It catalyzes ubiquinone (UQ) reduction by ETF, linking oxidation of fatty acids and some amino acids to the mitochondrial respiratory chain. Deficiencies in ETF or ETF-QO result in multiple acyl-CoA dehydrogenase deficiency, a human metabolic disease. Crystal structures of ETF-QO with and without bound UQ were determined, and they are essentially identical. The molecule forms a single structural domain. Three functional regions bind FAD, the 4Fe4S cluster, and UQ and are closely packed and share structural elements, resulting in no discrete structural domains. The UQ-binding pocket consists mainly of hydrophobic residues, and UQ binding differs from that of other UQ-binding proteins. ETF-QO is a monotopic integral membrane protein. The putative membrane-binding surface contains an alpha-helix and a beta-hairpin, forming a hydrophobic plateau. The UQ-flavin distance (8.5 A) is shorter than the UQ-cluster distance (18.8 A), and the very similar redox potentials of FAD and the cluster strongly suggest that the flavin, not the cluster, transfers electrons to UQ. Two possible electron transfer paths can be envisioned. First, electrons from the ETF flavin semiquinone may enter the ETF-QO flavin one by one, followed by rapid equilibration with the cluster. Alternatively, electrons may enter via the cluster, followed by equilibration between centers. In both cases, when ETF-QO is reduced to a two-electron reduced state (one electron at each redox center), the enzyme is primed to reduce UQ to ubiquinol via FAD.

 

==About this Structure==

2GMH is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Sus_scrofa Sus scrofa] with <scene name='pdbligand=BHG:'>BHG</scene>, <scene name='pdbligand=NA:'>NA</scene>, <scene name='pdbligand=SF4:'>SF4</scene>, <scene name='pdbligand=FAD:'>FAD</scene>, <scene name='pdbligand=UQ5:'>UQ5</scene> and <scene name='pdbligand=EDO:'>EDO</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Electron-transferring-flavoprotein_dehydrogenase Electron-transferring-flavoprotein dehydrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.5.5.1 1.5.5.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2GMH OCA].

 

==Reference==

Structure of electron transfer flavoprotein-ubiquinone oxidoreductase and electron transfer to the mitochondrial ubiquinone pool., Zhang J, Frerman FE, Kim JJ, Proc Natl Acad Sci U S A. 2006 Oct 31;103(44):16212-7. Epub 2006 Oct 18. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=17050691 17050691]

[[Category: Electron-transferring-flavoprotein dehydrogenase]]

[[Category: Single protein]]

[[Category: Frerman, F E.]]

[[Category: Kim, J J.P.]]

[[Category: Zhang, J.]]