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| | ==Crystal Structure of Ketosteroid Isomerase D38E from Pseudomonas Testosteroni (tKSI)== | | ==Crystal Structure of Ketosteroid Isomerase D38E from Pseudomonas Testosteroni (tKSI)== |
| - | <StructureSection load='4l7k' size='340' side='right' caption='[[4l7k]], [[Resolution|resolution]] 2.10Å' scene=''> | + | <StructureSection load='4l7k' size='340' side='right'caption='[[4l7k]], [[Resolution|resolution]] 2.10Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[4l7k]] is a 12 chain structure with sequence from [http://en.wikipedia.org/wiki/Atcc_11996 Atcc 11996]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4L7K OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4L7K FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[4l7k]] is a 12 chain structure with sequence from [https://en.wikipedia.org/wiki/Comamonas_testosteroni Comamonas testosteroni]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4L7K OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4L7K 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>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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]] 2.1Å</td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">ksi ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=285 ATCC 11996])</td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GOL:GLYCEROL'>GOL</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/Steroid_Delta-isomerase Steroid Delta-isomerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=5.3.3.1 5.3.3.1] </span></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=4l7k FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4l7k OCA], [https://pdbe.org/4l7k PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4l7k RCSB], [https://www.ebi.ac.uk/pdbsum/4l7k PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4l7k ProSAT]</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=4l7k FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4l7k OCA], [http://pdbe.org/4l7k PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=4l7k RCSB], [http://www.ebi.ac.uk/pdbsum/4l7k PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=4l7k ProSAT]</span></td></tr> | + | |
| | </table> | | </table> |
| - | <div style="background-color:#fffaf0;">
| + | == Function == |
| - | == Publication Abstract from PubMed == | + | [https://www.uniprot.org/uniprot/SDIS_COMTE SDIS_COMTE] |
| - | Although the cation-pi pair, formed between a side chain or substrate cation and the negative electrostatic potential of a pi system on the face of an aromatic ring, has been widely discussed and has been shown to be important in protein structure and protein-ligand interactions, there has been little discussion of the potential structural and functional importance in proteins of the related anion-aromatic pair (i.e., interaction of a negatively charged group with the positive electrostatic potential on the ring edge of an aromatic group). We posited, based on prior structural information, that anion-aromatic interactions between the anionic Asp general base and Phe54 and Phe116 might be used instead of a hydrogen-bond network to position the general base in the active site of ketosteroid isomerase from Comamonas testosteroni as there are no neighboring hydrogen-bonding groups. We have tested the role of the Phe residues using site-directed mutagenesis, double-mutant cycles, and high-resolution X-ray crystallography. These results indicate a catalytic role of these Phe residues. Extensive analysis of the Protein Data Bank provides strong support for a catalytic role of these and other Phe residues in providing anion-aromatic interactions that position anionic general bases within enzyme active sites. Our results further reveal a potential selective advantage of Phe in certain situations, relative to more traditional hydrogen-bonding groups, because it can simultaneously aid in the binding of hydrophobic substrates and positioning of a neighboring general base.
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| - | | + | |
| - | Use of anion-aromatic interactions to position the general base in the ketosteroid isomerase active site.,Schwans JP, Sunden F, Lassila JK, Gonzalez A, Tsai Y, Herschlag D Proc Natl Acad Sci U S A. 2013 Jul 9;110(28):11308-13. doi:, 10.1073/pnas.1206710110. Epub 2013 Jun 24. PMID:23798413<ref>PMID:23798413</ref>
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| - | | + | |
| - | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
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| - | </div>
| + | |
| - | <div class="pdbe-citations 4l7k" style="background-color:#fffaf0;"></div>
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| | | | |
| | ==See Also== | | ==See Also== |
| | *[[Ketosteroid Isomerase|Ketosteroid Isomerase]] | | *[[Ketosteroid Isomerase|Ketosteroid Isomerase]] |
| - | == References == | |
| - | <references/> | |
| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Atcc 11996]] | + | [[Category: Comamonas testosteroni]] |
| - | [[Category: Steroid Delta-isomerase]] | + | [[Category: Large Structures]] |
| - | [[Category: Gonzalez, A]] | + | [[Category: Gonzalez A]] |
| - | [[Category: Herschlag, D]] | + | [[Category: Herschlag D]] |
| - | [[Category: Schwans, J]] | + | [[Category: Schwans J]] |
| - | [[Category: Sunden, F]] | + | [[Category: Sunden F]] |
| - | [[Category: Tsai, Y]] | + | [[Category: Tsai Y]] |
| - | [[Category: Isomerase]]
| + | |
