View source for 6tjr


==Structure of HdrA-like subunit from Hyphomicrobium denitrificans==
<StructureSection load='6tjr' size='340' side='right'caption='[[6tjr]], [[Resolution|resolution]] 1.43&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6tjr]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Atcc_51888 Atcc 51888]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6TJR OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6TJR 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=MES:2-(N-MORPHOLINO)-ETHANESULFONIC+ACID'>MES</scene>, <scene name='pdbligand=SF4:IRON/SULFUR+CLUSTER'>SF4</scene></td></tr>
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">Hden_0691 ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=53399 ATCC 51888])</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=6tjr FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6tjr OCA], [https://pdbe.org/6tjr PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6tjr RCSB], [https://www.ebi.ac.uk/pdbsum/6tjr PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6tjr ProSAT]</span></td></tr>
</table>
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== Publication Abstract from PubMed ==
Many Bacteria and Archaea employ a novel pathway of sulfur oxidation involving an enzyme complex that is related to the heterodisulfide reductase (HdrABC) of methanogens. As a first step in the biochemical characterization of Hdr-like proteins from sulfur oxidizers (sHdr), we structurally analyzed the recombinant sHdrA protein from the Alphaproteobacterium Hyphomicrobium denitrificans at 1.4 A resolution. The sHdrA core structure is similar to that of methanogenic HdrA (mHdrA) which binds the electron-bifurcating flavin adenine dinucleotide (FAD), the heart of the HdrABC-[NiFe]-hydrogenase catalyzed reaction. Each sHdrA homodimer carries two FADs and two [4Fe-4S] clusters being linked by electron conductivity. Redox titrations monitored by electron paramagnetic resonance and visible spectroscopy revealed a redox potential between -203 and -188 mV for the [4Fe-4S] center. The potentials for the FADH*/FADH(-) and FAD/FADH* pairs reside between -174 and -156 mV and between -81 and -19 mV, respectively. The resulting stable semiquinone FADH* species, already detectable in the visible and EPR spectra of the as-isolated state of sHdrA is incompatible with basic principles of flavin-based electron bifurcation such that the sHdr complex does not apply this new mode of energy coupling. The inverted one-electron FAD redox potentials of sHdr and mHdr are clearly reflected in the different FAD-polypeptide interactions. According to this finding and the assumption that the sHdr complex forms an asymmetric HdrAA'B1C1B2C2 hexamer we tentatively propose a mechanism that links protein-bound sulfane oxidation to sulfite on HdrB1 with NAD(+) reduction via lipoamide disulfide reduction on HdrB2. The FAD of HdrA thereby serves as an electron storage unit.

Structural and spectroscopic characterization of a HdrA-like subunit from Hyphomicrobium denitrificans.,Ernst C, Kayastha K, Koch T, Venceslau SS, Pereira IAC, Demmer U, Ermler U, Dahl C FEBS J. 2020 Aug 4. doi: 10.1111/febs.15505. PMID:32750208<ref>PMID:32750208</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Atcc 51888]]
[[Category: Large Structures]]
[[Category: Dahl, C]]
[[Category: Ermler, U]]
[[Category: Kayastha, K]]
[[Category: Dissimilatory sulfur oxidation]]
[[Category: Electron bifurcation]]
[[Category: Fad]]
[[Category: Flavoprotein]]
[[Category: Heterodisulfide reductase]]