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== | ==HUMAN THROMBIN-INHIBITOR COMPLEX== | ||
<StructureSection load='1k22' size='340' side='right'caption='[[1k22]], [[Resolution|resolution]] 1.93Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[1k22]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Hirudo_medicinalis Hirudo medicinalis] and [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1K22 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1K22 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]] 1.93Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MEL:[((1R)-2-{(2S)-2-[({4-[AMINO(IMINO)METHYL]BENZYL}AMINO)CARBONYL]AZETIDINYL}-1-CYCLOHEXYL-2-OXOETHYL)AMINO]ACETIC+ACID'>MEL</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene>, <scene name='pdbligand=NAG:N-ACETYL-D-GLUCOSAMINE'>NAG</scene>, <scene name='pdbligand=TYS:O-SULFO-L-TYROSINE'>TYS</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=1k22 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1k22 OCA], [https://pdbe.org/1k22 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1k22 RCSB], [https://www.ebi.ac.uk/pdbsum/1k22 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1k22 ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/HIRV2_HIRME HIRV2_HIRME] Hirudin is a potent thrombin-specific protease inhibitor. It forms a stable non-covalent complex with alpha-thrombin, thereby abolishing its ability to cleave fibrinogen. | |||
== 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/k2/1k22_consurf.spt"</scriptWhenChecked> | |||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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=1k22 ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The binding of a series of low molecular weight ligands towards trypsin and thrombin has been studied by isothermal titration calorimetry and protein crystallography. In a series of congeneric ligands, surprising changes of protonation states occur and are overlaid on the binding process. They result from induced pK(a) shifts depending on the local environment experienced by the ligand and protein functional groups in the complex (induced dielectric fit). They involve additional heat effects that must be corrected before any conclusion on the binding enthalpy (DeltaH) and entropy (DeltaS) can be drawn. After correction, trends in both contributions can be interpreted in structural terms with respect to the hydrogen bond inventory or residual ligand motions. For all inhibitors studied, a strong negative heat capacity change (DeltaC(p)) is detected, thus binding becomes more exothermic and entropically less favourable with increasing temperature. Due to a mutual compensation, Gibbs free energy remains virtually unchanged. The strong negative DeltaC(p) value cannot solely be explained by the removal of hydrophobic surface portions of the protein or ligand from water exposure. Additional contributions must be considered, presumably arising from modulations of the local water structure, changes in vibrational modes or other ordering parameters. For thrombin, smaller negative DeltaC(p) values are observed for ligand binding in the presence of sodium ions compared to the other alkali ions, probably due to stabilising effects on the protein or changes in the bound water structure. | The binding of a series of low molecular weight ligands towards trypsin and thrombin has been studied by isothermal titration calorimetry and protein crystallography. In a series of congeneric ligands, surprising changes of protonation states occur and are overlaid on the binding process. They result from induced pK(a) shifts depending on the local environment experienced by the ligand and protein functional groups in the complex (induced dielectric fit). They involve additional heat effects that must be corrected before any conclusion on the binding enthalpy (DeltaH) and entropy (DeltaS) can be drawn. After correction, trends in both contributions can be interpreted in structural terms with respect to the hydrogen bond inventory or residual ligand motions. For all inhibitors studied, a strong negative heat capacity change (DeltaC(p)) is detected, thus binding becomes more exothermic and entropically less favourable with increasing temperature. Due to a mutual compensation, Gibbs free energy remains virtually unchanged. The strong negative DeltaC(p) value cannot solely be explained by the removal of hydrophobic surface portions of the protein or ligand from water exposure. Additional contributions must be considered, presumably arising from modulations of the local water structure, changes in vibrational modes or other ordering parameters. For thrombin, smaller negative DeltaC(p) values are observed for ligand binding in the presence of sodium ions compared to the other alkali ions, probably due to stabilising effects on the protein or changes in the bound water structure. | ||
Factorising ligand affinity: a combined thermodynamic and crystallographic study of trypsin and thrombin inhibition.,Dullweber F, Stubbs MT, Musil D, Sturzebecher J, Klebe G J Mol Biol. 2001 Oct 26;313(3):593-614. PMID:11676542<ref>PMID:11676542</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 1k22" style="background-color:#fffaf0;"></div> | |||
== | ==See Also== | ||
*[[Hirudin 3D structures|Hirudin 3D structures]] | |||
*[[Thrombin 3D Structures|Thrombin 3D Structures]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Hirudo medicinalis]] | [[Category: Hirudo medicinalis]] | ||
[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: Musil D]] | |||
[[Category: Musil | [[Category: Stubbs MT]] | ||
[[Category: Stubbs | |||
Latest revision as of 11:34, 6 November 2024
HUMAN THROMBIN-INHIBITOR COMPLEXHUMAN THROMBIN-INHIBITOR COMPLEX
Structural highlights
FunctionHIRV2_HIRME Hirudin is a potent thrombin-specific protease inhibitor. It forms a stable non-covalent complex with alpha-thrombin, thereby abolishing its ability to cleave fibrinogen. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe binding of a series of low molecular weight ligands towards trypsin and thrombin has been studied by isothermal titration calorimetry and protein crystallography. In a series of congeneric ligands, surprising changes of protonation states occur and are overlaid on the binding process. They result from induced pK(a) shifts depending on the local environment experienced by the ligand and protein functional groups in the complex (induced dielectric fit). They involve additional heat effects that must be corrected before any conclusion on the binding enthalpy (DeltaH) and entropy (DeltaS) can be drawn. After correction, trends in both contributions can be interpreted in structural terms with respect to the hydrogen bond inventory or residual ligand motions. For all inhibitors studied, a strong negative heat capacity change (DeltaC(p)) is detected, thus binding becomes more exothermic and entropically less favourable with increasing temperature. Due to a mutual compensation, Gibbs free energy remains virtually unchanged. The strong negative DeltaC(p) value cannot solely be explained by the removal of hydrophobic surface portions of the protein or ligand from water exposure. Additional contributions must be considered, presumably arising from modulations of the local water structure, changes in vibrational modes or other ordering parameters. For thrombin, smaller negative DeltaC(p) values are observed for ligand binding in the presence of sodium ions compared to the other alkali ions, probably due to stabilising effects on the protein or changes in the bound water structure. Factorising ligand affinity: a combined thermodynamic and crystallographic study of trypsin and thrombin inhibition.,Dullweber F, Stubbs MT, Musil D, Sturzebecher J, Klebe G J Mol Biol. 2001 Oct 26;313(3):593-614. PMID:11676542[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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