View source for 6kg1


==NifS from Helicobacter pylori, soaked with L-cysteine for 180 sec==
<StructureSection load='6kg1' size='340' side='right'caption='[[6kg1]], [[Resolution|resolution]] 2.70&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6kg1]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Helicobacter_pylori_26695 Helicobacter pylori 26695]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6KG1 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6KG1 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]] 2.7&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=IPA:ISOPROPYL+ALCOHOL'>IPA</scene>, <scene name='pdbligand=PDA:2-[(3-HYDROXY-2-METHYL-5-PHOSPHONOOXYMETHYL-PYRIDIN-4-YLMETHYL)-AMINO]-PROPIONIC+ACID'>PDA</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=6kg1 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6kg1 OCA], [https://pdbe.org/6kg1 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6kg1 RCSB], [https://www.ebi.ac.uk/pdbsum/6kg1 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6kg1 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/ISCS_HELPY ISCS_HELPY] Master enzyme that delivers sulfur to a number of partners involved in Fe-S cluster assembly, tRNA modification or cofactor biosynthesis. Catalyzes the removal of elemental sulfur atoms from cysteine to produce alanine. Functions as a sulfur delivery protein for Fe-S cluster synthesis onto IscU, an Fe-S scaffold assembly protein, as well as other S acceptor proteins.
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== Publication Abstract from PubMed ==
Cysteine desulfurase enzymes catalyze sulfur mobilization from l-cysteine to sulfur-containing biomolecules such as iron-sulfur (Fe-S) clusters and thio-tRNAs. The enzymes utilize the cofactor pyridoxal-5'-phosphate (PLP), which forms the external substrate- and product-aldimines and ketimines during catalysis and are grouped into two types (I and II) based on their different catalytic loops. To clarify the structure-based catalytic mechanisms for each group, we determined the structures of the external substrate- and product-aldimines as catalytic intermediates of NifS (type I) and SufS (type II) that are involved in Fe-S cluster biosynthesis using X-ray crystallographic snapshot analysis. As a common intermediate structure, the thiol group of the PLP-l-cysteine external aldimine is stabilized by the conserved histidine adjacent to PLP through a polar interaction. This interaction makes the thiol group orientated for subsequent nucleophilic attack by a conserved cysteine residue on the catalytic loop in the state of PLP-l-cysteine ketimine, which is formed from the PLP-l-cysteine aldimine. Unlike the intermediates, structural changes of the loops were different between the type I and II enzymes. In the type I enzyme, conformational and topological change of the loop is necessary for nucleophilic attack by the cysteine. In contrast, the loop in type II cysteine desulfurase enzymes showed no large conformational change; rather, it might possibly orient the thiol group of the catalytic cysteine for nucleophilic attack toward PLP-l-cysteine. The present structures allow a revision of the catalytic mechanism and may provide a clue for consideration of enzyme function, structural diversity, and evolution of cysteine desulfurase enzymes. DATABASE: Structural data are available in PDB database under the accession numbers 5WT2, 5WT4, 5ZSP, 5ZST, 5ZS9, 5ZSK, 5ZSO, 6KFZ, 6KG0, and 6KG1.

Snapshots of PLP-substrate and PLP-product external aldimines as intermediates in two types of cysteine desulfurase enzymes.,Nakamura R, Hikita M, Ogawa S, Takahashi Y, Fujishiro T FEBS J. 2019 Oct 6. doi: 10.1111/febs.15081. PMID:31587510<ref>PMID:31587510</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 6kg1" style="background-color:#fffaf0;"></div>

==See Also==
*[[Cysteine desulfurase 3D structures|Cysteine desulfurase 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Helicobacter pylori 26695]]
[[Category: Large Structures]]
[[Category: Fujishiro T]]
[[Category: Nakamura R]]
[[Category: Takahashi Y]]