View source for 2f91


==1.2A resolution structure of a crayfish trypsin complexed with a peptide inhibitor, SGTI==
<StructureSection load='2f91' size='340' side='right'caption='[[2f91]], [[Resolution|resolution]] 1.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2f91]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Pontastacus_leptodactylus Pontastacus leptodactylus]. This structure supersedes the now removed PDB entry [http://oca.weizmann.ac.il/oca-bin/send-pdb?obs=1&id=1yr4 1yr4]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2F91 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2F91 FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CD:CADMIUM+ION'>CD</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene></td></tr>
<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Trypsin Trypsin], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.21.4 3.4.21.4] </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=2f91 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2f91 OCA], [https://pdbe.org/2f91 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2f91 RCSB], [https://www.ebi.ac.uk/pdbsum/2f91 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2f91 ProSAT]</span></td></tr>
</table>
== Function ==
[[https://www.uniprot.org/uniprot/SGP1_SCHGR SGP1_SCHGR]] In vitro, SGPI-1/SGCI is active against alpha-chymotrypsin and trypsin while SGPI-2/SGTI is active against alpha-chymotrypsin and pancreatic elastase. 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/f9/2f91_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=2f91 ConSurf].
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== Publication Abstract from PubMed ==
Atomic resolution (&lt;or=1.2 A) serine protease intermediate structures revealed that the strength of the hydrogen bonds between the enzyme and the substrate changed during catalysis. The well-conserved hydrogen bonds of antiparallel beta-sheet between the enzyme and the substrate become significantly shorter in the transition from a Michaelis complex analogue (Pontastacus leptodactylus (narrow-fingered crayfish) trypsin (CFT) in complex with Schistocerca gregaria (desert locust) trypsin inhibitor (SGTI) at 1.2 A resolution) to an acyl-enzyme intermediate (N-acetyl-Asn-Pro-Ile acyl-enzyme intermediate of porcine pancreatic elastase at 0.95 A resolution) presumably synchronously with the nucleophilic attack on the carbonyl carbon atom of the scissile peptide bond. This is interpreted as an active mechanism that utilizes the energy released from the stronger hydrogen bonds to overcome the energetic barrier of the nucleophilic attack by the hydroxyl group of the catalytic serine. In the CFT:SGTI complex this hydrogen bond shortening may be hindered by the 27I-32I disulfide bridge and Asn-15I of SGTI. The position of the catalytic histidine changes slightly as it adapts to the different nucleophilic attacker during the transition from the Michaelis complex to the acyl-enzyme state, and simultaneously its interaction with Asp-102 and Ser-214 becomes stronger. The oxyanion hole hydrogen bonds provide additional stabilization for acyl-ester bond in the acyl-enzyme than for scissile peptide bond of the Michaelis complex. Significant deviation from planarity is not observed in the reactive bonds of either the Michaelis complex or the acyl-enzyme. In the Michaelis complex the electron distribution of the carbonyl bond is distorted toward the oxygen atom compared to other peptide bonds in the structure, which indicates the polarization effect of the oxyanion hole.

Enzyme:substrate hydrogen bond shortening during the acylation phase of serine protease catalysis.,Fodor K, Harmat V, Neutze R, Szilagyi L, Graf L, Katona G Biochemistry. 2006 Feb 21;45(7):2114-21. PMID:16475800<ref>PMID:16475800</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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==See Also==
*[[Trypsin 3D structures|Trypsin 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Pontastacus leptodactylus]]
[[Category: Trypsin]]
[[Category: Antal, J]]
[[Category: Fodor, K]]
[[Category: Graf, L]]
[[Category: Harmat, V]]
[[Category: Hetenyi, C]]
[[Category: Kardos, J]]
[[Category: Katona, G]]
[[Category: Patthy, A]]
[[Category: Perczel, A]]
[[Category: Atomic resolution]]
[[Category: Canonical inhibitor]]
[[Category: Hydrolase-hydrolase inhibitor complex]]
[[Category: Serine protease]]