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| | ==Crystal Structure of MshB with glycerol and Acetate bound in the active site== | | ==Crystal Structure of MshB with glycerol and Acetate bound in the active site== |
| - | <StructureSection load='4ewl' size='340' side='right' caption='[[4ewl]], [[Resolution|resolution]] 1.85Å' scene=''> | + | <StructureSection load='4ewl' size='340' side='right'caption='[[4ewl]], [[Resolution|resolution]] 1.85Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[4ewl]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/"bacillus_tuberculosis"_(zopf_1883)_klein_1884 "bacillus tuberculosis" (zopf 1883) klein 1884]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4EWL OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4EWL FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[4ewl]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Mycobacterium_tuberculosis Mycobacterium tuberculosis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4EWL OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4EWL FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=PE4:2-{2-[2-(2-{2-[2-(2-ETHOXY-ETHOXY)-ETHOXY]-ETHOXY}-ETHOXY)-ETHOXY]-ETHOXY}-ETHANOL'>PE4</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr> | + | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=PE4:2-{2-[2-(2-{2-[2-(2-ETHOXY-ETHOXY)-ETHOXY]-ETHOXY}-ETHOXY)-ETHOXY]-ETHOXY}-ETHANOL'>PE4</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">mshB, MT1207, Rv1170 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=1773 "Bacillus tuberculosis" (Zopf 1883) Klein 1884])</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=4ewl FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4ewl OCA], [https://pdbe.org/4ewl PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4ewl RCSB], [https://www.ebi.ac.uk/pdbsum/4ewl PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4ewl ProSAT]</span></td></tr> |
| - | <tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/N-acetyl-1-D-myo-inositol-2-amino-2-deoxy-alpha-D-glucopyranoside_deacetylase N-acetyl-1-D-myo-inositol-2-amino-2-deoxy-alpha-D-glucopyranoside deacetylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.1.103 3.5.1.103] </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=4ewl FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4ewl OCA], [http://pdbe.org/4ewl PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=4ewl RCSB], [http://www.ebi.ac.uk/pdbsum/4ewl PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=4ewl ProSAT]</span></td></tr> | + | |
| | </table> | | </table> |
| | == Function == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/MSHB_MYCTU MSHB_MYCTU]] Catalyzes the deacetylation of 1D-myo-inositol 2-acetamido-2-deoxy-alpha-D-glucopyranoside (GlcNAc-Ins) in the mycothiol (MSH) biosynthesis pathway. Shows some amidase activity toward S-conjugates of mycothiol.<ref>PMID:11092856</ref> | + | [https://www.uniprot.org/uniprot/MSHB_MYCTU MSHB_MYCTU] Catalyzes the deacetylation of 1D-myo-inositol 2-acetamido-2-deoxy-alpha-D-glucopyranoside (GlcNAc-Ins) in the mycothiol (MSH) biosynthesis pathway. Shows some amidase activity toward S-conjugates of mycothiol.<ref>PMID:11092856</ref> |
| | <div style="background-color:#fffaf0;"> | | <div style="background-color:#fffaf0;"> |
| | == Publication Abstract from PubMed == | | == Publication Abstract from PubMed == |
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| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: N-acetyl-1-D-myo-inositol-2-amino-2-deoxy-alpha-D-glucopyranoside deacetylase]] | + | [[Category: Large Structures]] |
| - | [[Category: Broadley, S G]] | + | [[Category: Mycobacterium tuberculosis]] |
| - | [[Category: Marakalala, M J]] | + | [[Category: Broadley SG]] |
| - | [[Category: Sewell, B T]] | + | [[Category: Marakalala MJ]] |
| - | [[Category: Steenkamp, D J]] | + | [[Category: Sewell BT]] |
| - | [[Category: Weber, B W]] | + | [[Category: Steenkamp DJ]] |
| - | [[Category: Acetate]] | + | [[Category: Weber BW]] |
| - | [[Category: Active site]]
| + | |
| - | [[Category: Glycerol]]
| + | |
| - | [[Category: Histidine 144]]
| + | |
| - | [[Category: Hydrolase]]
| + | |
| - | [[Category: Mshb]]
| + | |
| - | [[Category: Tyrosine 142]]
| + | |
| Structural highlights
Function
MSHB_MYCTU Catalyzes the deacetylation of 1D-myo-inositol 2-acetamido-2-deoxy-alpha-D-glucopyranoside (GlcNAc-Ins) in the mycothiol (MSH) biosynthesis pathway. Shows some amidase activity toward S-conjugates of mycothiol.[1]
Publication Abstract from PubMed
MshB, a zinc-based deacetylase, catalyses a step in the mycothiol biosynthetic pathway that involves the deacetylation of 1-O-(2-acetamido-2-deoxy-alpha-D-glucopyranosyl)-D-myo-inositol (GlcNAc-Ins), via cleavage of an amide bond, to 1-O-(2-amino-2-deoxy-alpha-D-glucopyranosyl)-D-myo-inositol (GlcN-Ins) and acetate. In this study, MshB was expressed, purified and crystallized. A new crystal form was encountered in 0.1 M sodium acetate, 0.2 M ammonium sulfate, 25% PEG 4000 pH 4.6. The crystals diffracted to 1.95 A resolution and the resulting electron-density map revealed glycerol and the reaction product, acetate, in the active site. These ligands enabled the natural substrate GlcNAc-Ins to be modelled in the active site with some certainty. One acetate O atom is hydrogen bonded to Tyr142 and is located 2.5 A from the catalytic zinc. The other acetate O atom is located 2.7 A from a carboxylate O atom of Asp15. This configuration strongly suggests that Asp15 acts both as a general base catalyst in the nucleophilic attack of water on the amide carbonyl C atom and in its protonated form acts as a general acid to protonate the amide N atom. The configuration of Tyr142 differs from that observed previously in crystal structures of MshB (PDB entries 1q74 and 1q7t) and its location provides direct structural support for recently published biochemical and mutational studies suggesting that this residue is involved in a conformational change on substrate binding and contributes to the oxyanion hole that stabilizes the tetrahedral intermediate.
A new crystal form of MshB from Mycobacterium tuberculosis with glycerol and acetate in the active site suggests the catalytic mechanism.,Broadley SG, Gumbart JC, Weber BW, Marakalala MJ, Steenkamp DJ, Sewell BT Acta Crystallogr D Biol Crystallogr. 2012 Nov;68(Pt 11):1450-9. doi:, 10.1107/S090744491203449X. Epub 2012 Oct 13. PMID:23090394[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Newton GL, Av-Gay Y, Fahey RC. N-Acetyl-1-D-myo-inosityl-2-amino-2-deoxy-alpha-D-glucopyranoside deacetylase (MshB) is a key enzyme in mycothiol biosynthesis. J Bacteriol. 2000 Dec;182(24):6958-63. PMID:11092856
- ↑ Broadley SG, Gumbart JC, Weber BW, Marakalala MJ, Steenkamp DJ, Sewell BT. A new crystal form of MshB from Mycobacterium tuberculosis with glycerol and acetate in the active site suggests the catalytic mechanism. Acta Crystallogr D Biol Crystallogr. 2012 Nov;68(Pt 11):1450-9. doi:, 10.1107/S090744491203449X. Epub 2012 Oct 13. PMID:23090394 doi:http://dx.doi.org/10.1107/S090744491203449X
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