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| | ==The structure of AhpE from Mycobacterium tuberculosis revisited== | | ==The structure of AhpE from Mycobacterium tuberculosis revisited== |
| - | <StructureSection load='4x1u' size='340' side='right' caption='[[4x1u]], [[Resolution|resolution]] 1.87Å' scene=''> | + | <StructureSection load='4x1u' size='340' side='right'caption='[[4x1u]], [[Resolution|resolution]] 1.87Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[4x1u]] is a 2 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4X1U OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4X1U FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[4x1u]] 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=4X1U OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4X1U FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=GOL:GLYCEROL'>GOL</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.87Å</td></tr> |
| - | <tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=CSO:S-HYDROXYCYSTEINE'>CSO</scene></td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CSO:S-HYDROXYCYSTEINE'>CSO</scene>, <scene name='pdbligand=GOL:GLYCEROL'>GOL</scene></td></tr> |
| - | <tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[1xvw|1xvw]]</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=4x1u FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4x1u OCA], [https://pdbe.org/4x1u PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4x1u RCSB], [https://www.ebi.ac.uk/pdbsum/4x1u PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4x1u 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/Peroxiredoxin Peroxiredoxin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.11.1.15 1.11.1.15] </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=4x1u FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4x1u OCA], [http://pdbe.org/4x1u PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=4x1u RCSB], [http://www.ebi.ac.uk/pdbsum/4x1u PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=4x1u ProSAT]</span></td></tr> | + | |
| | </table> | | </table> |
| | + | == Function == |
| | + | [https://www.uniprot.org/uniprot/AHPE_MYCTU AHPE_MYCTU] Thiol-specific peroxidase that catalyzes the reduction of hydrogen peroxide and organic hydroperoxides to water and alcohols, respectively. Plays a role in cell protection against oxidative stress by detoxifying peroxides. May represent an important antioxidant defense against cytotoxic peroxides, especially peroxynitrite, which can be formed by activated macrophages during infection.<ref>PMID:19737009</ref> <ref>PMID:24379404</ref> |
| | <div style="background-color:#fffaf0;"> | | <div style="background-color:#fffaf0;"> |
| | == Publication Abstract from PubMed == | | == Publication Abstract from PubMed == |
| - | All living systems require protection against the damaging effects of reactive oxygen species. The genome of Mycobacterium tuberculosis, the cause of TB, encodes a number of peroxidases that are thought to be active against organic and inorganic peroxides, and are likely to play a key role in the ability of this organism to survive within the phagosomes of macrophages. The open reading frame Rv2238c in M.tuberculosis encodes a 153-residue protein AhpE, which is a peroxidase of the 1-Cys peroxiredoxin (Prx) family. The crystal structure of AhpE, determined at 1.87 A resolution (R(cryst)=0.179, R(free)=0.210), reveals a compact single-domain protein with a thioredoxin fold. AhpE forms both dimers and octamers; a tightly-associated dimer and a ring-like octamer, generated by crystallographic 4-fold symmetry. In this native structure, the active site Cys45 is in its oxidized, sulfenic acid (S-O-H) state. A second crystal form of AhpE, obtained after soaking in sodium bromide and refined at 1.90 A resolution (R(cryst)=0.242, R(free)=0.286), reveals the reduced structure. In this structure, a conformational change in an external loop, in two of the four molecules in the asymmetric unit, allows Arg116 to stabilise the Cys45 thiolate ion, and concomitantly closes a surface channel. This channel is identified as the likely binding site for a physiological reductant, and the conformational change is inferred to be important for the reaction cycle of AhpE.
| + | In many established methods, identification of hydrogen bonds (H-bonds) is primarily based on pairwise comparison of distances between atoms. These methods often give rise to systematic errors when sulfur is involved. A more accurate method is the non-covalent interaction index, which determines the strength of the H-bonds based on the associated electron density and its gradient. We applied the NCI index on the active site of a single-cysteine peroxiredoxin. We found a different sulfur hydrogen-bonding network to that typically found by established methods, and we propose a more accurate equation for determining sulfur H-bonds based on geometrical criteria. This new algorithm will be implemented in the next release of the widely-used CHARMM program (version 41b), and will be particularly useful for analyzing water molecule-mediated H-bonds involving different atom types. Furthermore, based on the identification of the weakest sulfur-water H-bond, the location of hydrogen peroxide for the nucleophilic attack by the cysteine sulfur can be predicted. In general, current methods to determine H-bonds will need to be reevaluated, thereby leading to better understanding of the catalytic mechanisms in which sulfur chemistry is involved. |
| | | | |
| - | Crystal Structure of AhpE from Mycobacterium tuberculosis, a 1-Cys peroxiredoxin.,Li S, Peterson NA, Kim MY, Kim CY, Hung LW, Yu M, Lekin T, Segelke BW, Lott JS, Baker EN J Mol Biol. 2005 Mar 4;346(4):1035-46. Epub 2005 Jan 25. PMID:15701515<ref>PMID:15701515</ref>
| + | Revisiting sulfur H-bonds in proteins: The example of peroxiredoxin AhpE.,van Bergen LA, Alonso M, Pallo A, Nilsson L, De Proft F, Messens J Sci Rep. 2016 Jul 29;6:30369. doi: 10.1038/srep30369. PMID:27468924<ref>PMID:27468924</ref> |
| | | | |
| | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> |
| | </div> | | </div> |
| | <div class="pdbe-citations 4x1u" style="background-color:#fffaf0;"></div> | | <div class="pdbe-citations 4x1u" style="background-color:#fffaf0;"></div> |
| | + | |
| | + | ==See Also== |
| | + | *[[Thioredoxin reductase 3D structures|Thioredoxin reductase 3D structures]] |
| | == References == | | == References == |
| | <references/> | | <references/> |
| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Peroxiredoxin]] | + | [[Category: Large Structures]] |
| - | [[Category: Messens, J]] | + | [[Category: Mycobacterium tuberculosis]] |
| - | [[Category: Pallo, A]] | + | [[Category: Messens J]] |
| - | [[Category: Oxidoreductase]] | + | [[Category: Pallo A]] |
| Structural highlights
Function
AHPE_MYCTU Thiol-specific peroxidase that catalyzes the reduction of hydrogen peroxide and organic hydroperoxides to water and alcohols, respectively. Plays a role in cell protection against oxidative stress by detoxifying peroxides. May represent an important antioxidant defense against cytotoxic peroxides, especially peroxynitrite, which can be formed by activated macrophages during infection.[1] [2]
Publication Abstract from PubMed
In many established methods, identification of hydrogen bonds (H-bonds) is primarily based on pairwise comparison of distances between atoms. These methods often give rise to systematic errors when sulfur is involved. A more accurate method is the non-covalent interaction index, which determines the strength of the H-bonds based on the associated electron density and its gradient. We applied the NCI index on the active site of a single-cysteine peroxiredoxin. We found a different sulfur hydrogen-bonding network to that typically found by established methods, and we propose a more accurate equation for determining sulfur H-bonds based on geometrical criteria. This new algorithm will be implemented in the next release of the widely-used CHARMM program (version 41b), and will be particularly useful for analyzing water molecule-mediated H-bonds involving different atom types. Furthermore, based on the identification of the weakest sulfur-water H-bond, the location of hydrogen peroxide for the nucleophilic attack by the cysteine sulfur can be predicted. In general, current methods to determine H-bonds will need to be reevaluated, thereby leading to better understanding of the catalytic mechanisms in which sulfur chemistry is involved.
Revisiting sulfur H-bonds in proteins: The example of peroxiredoxin AhpE.,van Bergen LA, Alonso M, Pallo A, Nilsson L, De Proft F, Messens J Sci Rep. 2016 Jul 29;6:30369. doi: 10.1038/srep30369. PMID:27468924[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Hugo M, Turell L, Manta B, Botti H, Monteiro G, Netto LE, Alvarez B, Radi R, Trujillo M. Thiol and sulfenic acid oxidation of AhpE, the one-cysteine peroxiredoxin from Mycobacterium tuberculosis: kinetics, acidity constants, and conformational dynamics. Biochemistry. 2009 Oct 13;48(40):9416-26. PMID:19737009 doi:10.1021/bi901221s
- ↑ Hugo M, Van Laer K, Reyes AM, Vertommen D, Messens J, Radi R, Trujillo M. Mycothiol/mycoredoxin 1-dependent reduction of the peroxiredoxin AhpE from Mycobacterium tuberculosis. J Biol Chem. 2014 Feb 21;289(8):5228-39. PMID:24379404 doi:10.1074/jbc.M113.510248
- ↑ van Bergen LA, Alonso M, Pallo A, Nilsson L, De Proft F, Messens J. Revisiting sulfur H-bonds in proteins: The example of peroxiredoxin AhpE. Sci Rep. 2016 Jul 29;6:30369. doi: 10.1038/srep30369. PMID:27468924 doi:http://dx.doi.org/10.1038/srep30369
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