View source for 5udg


==Mutant E97Q crystal structure of Bacillus subtilis QueF with a disulfide Cys 55-99==
<StructureSection load='5udg' size='340' side='right'caption='[[5udg]], [[Resolution|resolution]] 2.50&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5udg]] is a 5 chain structure with sequence from [https://en.wikipedia.org/wiki/Bacillus_subtilis Bacillus subtilis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5UDG OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5UDG 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]] 2.5&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=PGE:TRIETHYLENE+GLYCOL'>PGE</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=5udg FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5udg OCA], [https://pdbe.org/5udg PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5udg RCSB], [https://www.ebi.ac.uk/pdbsum/5udg PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5udg ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/QUEF_BACSU QUEF_BACSU] Catalyzes the NADPH-dependent reduction of 7-cyano-7-deazaguanine (preQ0) to 7-aminomethyl-7-deazaguanine (preQ1), a late step in the queuosine pathway.<ref>PMID:15767583</ref> <ref>PMID:17929836</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
QueF enzymes catalyze the nicotinamide adenine dinucleotide phosphate (NADPH)-dependent reduction of the nitrile group of 7-cyano-7-deazaguanine (preQ(0)) to 7-aminomethyl-7-deazaguanine (preQ(1)) in the biosynthetic pathway to the tRNA modified nucleoside queuosine. The QueF-catalyzed reaction includes formation of a covalent thioimide intermediate with a conserved active site cysteine that is prone to oxidation in vivo. Here, we report the crystal structure of a mutant of Bacillus subtilis QueF, which reveals an unanticipated intramolecular disulfide formed between the catalytic Cys55 and a conserved Cys99 located near the active site. This structure is more symmetric than the substrate-bound structure and exhibits major rearrangement of the loops responsible for substrate binding. Mutation of Cys99 to Ala/Ser does not compromise enzyme activity, indicating that the disulfide does not play a catalytic role. Peroxide-induced inactivation of the wild-type enzyme is reversible with thioredoxin, while such inactivation of the Cys99Ala/Ser mutants is irreversible, consistent with protection of Cys55 from irreversible oxidation by disulfide formation with Cys99. Conservation of the cysteine pair, and the reported in vivo interaction of QueF with the thioredoxin-like hydroperoxide reductase AhpC in Escherichia coli suggest that regulation by the thioredoxin disulfide-thiol exchange system may constitute a general mechanism for protection of QueF from oxidative stress in vivo.

Protection of the Queuosine Biosynthesis Enzyme QueF from Irreversible Oxidation by a Conserved Intramolecular Disulfide.,Mohammad A, Bon Ramos A, Lee BW, Cohen SW, Kiani MK, Iwata-Reuyl D, Stec B, Swairjo MA Biomolecules. 2017 Mar 16;7(1). pii: E30. doi: 10.3390/biom7010030. PMID:28300774<ref>PMID:28300774</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5udg" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Bacillus subtilis]]
[[Category: Large Structures]]
[[Category: Iwata-Reuyl D]]
[[Category: Kiani MK]]
[[Category: Mohammad A]]
[[Category: Stec B]]
[[Category: Swairjo M]]