View source for 5cmx


==X-ray structure of the complex between human alpha thrombin and a duplex/quadruplex 31-mer DNA aptamer==
<StructureSection load='5cmx' size='340' side='right'caption='[[5cmx]], [[Resolution|resolution]] 2.98&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5cmx]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] and [https://en.wikipedia.org/wiki/Synthetic_construct Synthetic construct]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5CMX OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5CMX 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]] 2.98&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=0G6:D-PHENYLALANYL-N-[(2S,3S)-6-{[AMINO(IMINIO)METHYL]AMINO}-1-CHLORO-2-HYDROXYHEXAN-3-YL]-L-PROLINAMIDE'>0G6</scene>, <scene name='pdbligand=K:POTASSIUM+ION'>K</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=5cmx FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5cmx OCA], [https://pdbe.org/5cmx PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5cmx RCSB], [https://www.ebi.ac.uk/pdbsum/5cmx PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5cmx ProSAT]</span></td></tr>
</table>
== Disease ==
[https://www.uniprot.org/uniprot/THRB_HUMAN THRB_HUMAN] Defects in F2 are the cause of factor II deficiency (FA2D) [MIM:[https://omim.org/entry/613679 613679]. It is a very rare blood coagulation disorder characterized by mucocutaneous bleeding symptoms. The severity of the bleeding manifestations correlates with blood factor II levels.<ref>PMID:14962227</ref> <ref>PMID:6405779</ref> <ref>PMID:3771562</ref> <ref>PMID:3567158</ref> <ref>PMID:3801671</ref> <ref>PMID:3242619</ref> <ref>PMID:2719946</ref> <ref>PMID:1354985</ref> <ref>PMID:1421398</ref> <ref>PMID:1349838</ref> <ref>PMID:7865694</ref> <ref>PMID:7792730</ref>   Genetic variations in F2 may be a cause of susceptibility to ischemic stroke (ISCHSTR) [MIM:[https://omim.org/entry/601367 601367]; also known as cerebrovascular accident or cerebral infarction. A stroke is an acute neurologic event leading to death of neural tissue of the brain and resulting in loss of motor, sensory and/or cognitive function. Ischemic strokes, resulting from vascular occlusion, is considered to be a highly complex disease consisting of a group of heterogeneous disorders with multiple genetic and environmental risk factors.<ref>PMID:15534175</ref>   Defects in F2 are the cause of thrombophilia due to thrombin defect (THPH1) [MIM:[https://omim.org/entry/188050 188050]. It is a multifactorial disorder of hemostasis characterized by abnormal platelet aggregation in response to various agents and recurrent thrombi formation. Note=A common genetic variation in the 3-prime untranslated region of the prothrombin gene is associated with elevated plasma prothrombin levels and an increased risk of venous thrombosis.  Defects in F2 are associated with susceptibility to pregnancy loss, recurrent, type 2 (RPRGL2) [MIM:[https://omim.org/entry/614390 614390]. A common complication of pregnancy, resulting in spontaneous abortion before the fetus has reached viability. The term includes all miscarriages from the time of conception until 24 weeks of gestation. Recurrent pregnancy loss is defined as 3 or more consecutive spontaneous abortions.<ref>PMID:11506076</ref> 
== Function ==
[https://www.uniprot.org/uniprot/THRB_HUMAN THRB_HUMAN] Thrombin, which cleaves bonds after Arg and Lys, converts fibrinogen to fibrin and activates factors V, VII, VIII, XIII, and, in complex with thrombomodulin, protein C. Functions in blood homeostasis, inflammation and wound healing.<ref>PMID:2856554</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Mixed duplex/quadruplex oligonucleotides have attracted great interest as therapeutic targets as well as effective biomedical aptamers. In the case of thrombin-binding aptamer (TBA), the addition of a duplex motif to the G-quadruplex module improves the aptamer resistance to biodegradation and the affinity for thrombin. In particular, the mixed oligonucleotide RE31 is significantly more effective than TBA in anticoagulation experiments and shows a slower disappearance rate in human plasma and blood. In the crystal structure of the complex with thrombin, RE31 adopts an elongated structure in which the duplex and quadruplex regions are perfectly stacked on top of each other, firmly connected by a well-structured junction. The lock-and-key shape complementarity between the TT loops of the G-quadruplex and the protein exosite I gives rise to the basic interaction that stabilizes the complex. However, our data suggest that the duplex motif may have an active role in determining the greater anti-thrombin activity in biological fluids with respect to TBA. This work gives new information on mixed oligonucleotides and highlights the importance of structural data on duplex/quadruplex junctions, which appear to be varied, unpredictable, and fundamental in determining the aptamer functional properties.

Different duplex/quadruplex junctions determine the properties of anti-thrombin aptamers with mixed folding.,Russo Krauss I, Spiridonova V, Pica A, Napolitano V, Sica F Nucleic Acids Res. 2015 Dec 15. pii: gkv1384. PMID:26673709<ref>PMID:26673709</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5cmx" style="background-color:#fffaf0;"></div>

==See Also==
*[[Thrombin 3D Structures|Thrombin 3D Structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Synthetic construct]]
[[Category: Napolitano V]]
[[Category: Pica A]]
[[Category: Russo Krauss I]]
[[Category: Sica F]]