1s3c

<StructureSection load='1s3c' size='340' side='right' caption='[[1s3c]], [[Resolution|resolution]] 1.25&Aring;' scene=''>

<table><tr><td colspan='2'>[[1s3c]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/"bacillus_coli"_migula_1895 "bacillus coli" migula 1895]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1S3C OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1S3C FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CS:CESIUM+ION'>CS</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Arsenate_reductase_(glutaredoxin) Arsenate reductase (glutaredoxin)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.20.4.1 1.20.4.1] </span></td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1s3c FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1s3c OCA], [http://pdbe.org/1s3c PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1s3c RCSB], [http://www.ebi.ac.uk/pdbsum/1s3c PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1s3c ProSAT]</span></td></tr>

[[http://www.uniprot.org/uniprot/ARSC1_ECOLX ARSC1_ECOLX]] Reduction of arsenate [As(V)] to arsenite [As(III)]. This protein expands the substrate specificity of ArsAB pump which can extrude arsenite and antimonite to allow for arsenate pumping and resistance.

<scriptWhenChecked>select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/s3/1s3c_consurf.spt"</scriptWhenChecked>

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== Publication Abstract from PubMed ==

Arsenic is a ubiquitous environmental toxic metal. Consequently, organisms detoxify arsenate by reduction to arsenite, which is then excreted or sequestered. The ArsC arsenate reductase from Escherichia coli plasmid R773, the best characterized arsenic-modifying enzyme, has a catalytic cysteine, Cys 12, in the active site, surrounded by an arginine triad composed of Arg 60, Arg 94, and Arg 107. During the reaction cycle, the native enzyme forms a unique monohydroxyl Cys 12-thiol-arsenite adduct that contains a positive charge on the arsenic. We hypothesized previously that this unstable intermediate allows for rapid dissociation of the product arsenite. In this study, the role of Arg 60 in product formation was evaluated by mutagenesis. A total of eight new structures of ArsC were determined at resolutions between 1.3 A and 1.8 A, with R(free) values between 0.18 and 0.25. The crystal structures of R60K and R60A ArsC equilibrated with the product arsenite revealed a covalently bound Cys 12-thiol-dihydroxyarsenite without a charge on the arsenic atom. We propose that this intermediate is more stable than the monohydroxyarsenite intermediate of the native enzyme, resulting in slow release of product and, consequently, loss of activity.

 

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== References ==

[[Category: Bacillus coli migula 1895]]

[[Category: DeMel, S]]

[[Category: Edwards, B F]]

[[Category: Arsc]]

[[Category: Reductase]]