View source for 1jrx


==Crystal structure of Arg402Ala mutant flavocytochrome c3 from Shewanella frigidimarina==
<StructureSection load='1jrx' size='340' side='right'caption='[[1jrx]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1jrx]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Shewanella_frigidimarina Shewanella frigidimarina]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1JRX OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1JRX FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2&#8491;</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=FUM:FUMARIC+ACID'>FUM</scene>, <scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene></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=1jrx FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1jrx OCA], [https://pdbe.org/1jrx PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1jrx RCSB], [https://www.ebi.ac.uk/pdbsum/1jrx PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1jrx ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/FRDA_SHEFR FRDA_SHEFR] Catalyzes fumarate reduction using artificial electron donors such as methyl viologen. The physiological reductant is unknown, but evidence indicates that flavocytochrome c participates in electron transfer from formate to fumarate and possibly also to trimethylamine oxide (TMAO). This enzyme is essentially unidirectional.
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/jr/1jrx_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1jrx ConSurf].
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== Publication Abstract from PubMed ==
There is now overwhelming evidence supporting a common mechanism for fumarate reduction in the respiratory fumarate reductases. The X-ray structures of substrate-bound forms of these enzymes indicate that the substrate is well positioned to accept a hydride from FAD and a proton from an arginine side chain. Recent work on the enzyme from Shewanella frigidimarina [Doherty, M. K., Pealing, S. L., Miles, C. S., Moysey, R., Taylor, P., Walkinshaw, M. D., Reid, G. A., and Chapman, S. K. (2000) Biochemistry 39, 10695-10701] has strengthened the assignment of an arginine (Arg402) as the proton donor in fumarate reduction. Here we describe the crystallographic and kinetic analyses of the R402A, R402K, and R402Y mutant forms of the Shewanella enzyme. The crystal structure of the R402A mutant (2.0 A resolution) shows it to be virtually identical to the wild-type enzyme, apart from the fact that a water molecule occupies the position previously taken by part of the guanidine group of R402. Although structurally similar to the wild-type enzyme, the R402A mutant is inactive under all the conditions that were studied. This implies that a water molecule, in this position in the active site, cannot function as the proton donor for fumarate reduction. In contrast to the R402A mutation, both the R402K and R402Y mutant enzymes are active. Although this activity was at a very low level (at pH 7.2 some 10(4)-fold lower than that for the wild type), it does imply that both lysine and tyrosine can fulfill the role of an active site proton donor, albeit very poorly. The crystal structures of the R402K and R402Y mutant enzymes (2.0 A resolution) show that distances from the lysine and tyrosine side chains to the nearest carbon atom of fumarate are approximately 3.5 A, clearly permitting proton transfer. The combined results from mutagenesis, crystallographic, and kinetic studies provide formidable evidence that R402 acts as both a Lewis acid (stabilizing the build-up of negative charge upon hydride transfer from FAD to fumarate) and a Bronsted acid (donating the proton to the substrate to complete the formation of succinate).

Kinetic and crystallographic analysis of the key active site acid/base arginine in a soluble fumarate reductase.,Mowat CG, Moysey R, Miles CS, Leys D, Doherty MK, Taylor P, Walkinshaw MD, Reid GA, Chapman SK Biochemistry. 2001 Oct 16;40(41):12292-8. PMID:11591148<ref>PMID:11591148</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Flavocytochrome 3D structures|Flavocytochrome 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Shewanella frigidimarina]]
[[Category: Chapman SK]]
[[Category: Doherty MK]]
[[Category: Leys D]]
[[Category: Miles CS]]
[[Category: Mowat CG]]
[[Category: Moysey R]]
[[Category: Reid GA]]
[[Category: Taylor P]]
[[Category: Walkinshaw MD]]