1hgt
From Proteopedia
(New page: 200px<br /> <applet load="1hgt" size="450" color="white" frame="true" align="right" spinBox="true" caption="1hgt, resolution 2.2Å" /> '''STRUCTURE OF THE HIR...) |
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caption="1hgt, resolution 2.2Å" /> | caption="1hgt, resolution 2.2Å" /> | ||
'''STRUCTURE OF THE HIRUGEN AND HIRULOG 1 COMPLEXES OF ALPHA-THROMBIN'''<br /> | '''STRUCTURE OF THE HIRUGEN AND HIRULOG 1 COMPLEXES OF ALPHA-THROMBIN'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The isomorphous structures of the hirugen (N-acetylhirudin 53'-64' with | + | The isomorphous structures of the hirugen (N-acetylhirudin 53'-64' with sulfato-Tyr63') and hirulog 1 (D-Phe-Pro-Arg-Pro-(Gly)4 desulfato-Tyr63'-hirugen) complexes of human alpha-thrombin have been determined and refined at 2.2 A resolution to crystallographic R-factors of 0.167 and 0.163, respectively. The binding of hirugen to thrombin is similar to that of the binding of the C-terminal dodecapeptide of hirudin, including that of the terminal 3(10) helical turn. The sulfato Tyr63', which, as a result of sulfation, increases the binding affinity by an order of magnitude, is involved in an extended hydrogen bonding network utilizing all three sulfato oxygen atoms. The hirugen-thrombin complex is the first thrombin structure determined to have an unobstructed active site; this site is practically identical in positioning of catalytic residues and in its hydrogen bonding pattern with that of other serine proteinases. Hirulog 1, which is a poor thrombin substrate, is cleaved at the Arg3'-Pro4' bond in the crystal structure. The Arg3' of hirulog 1 occupies the specificity site, the D-Phe-Pro-Arg tripeptide is positioned like that of D-Phe-Pro-Arg chloromethylketone in the active site and the Pro4'(Gly)4 spacer to hirugen is disordered in the structure, as is the 3(10) turn of hirugen. The latter must be related to the simultaneous absence both of sulfation and of the last residue of hirudin (Gln65'). In addition, the autolysis loop of thrombin (Lys145-Gly150) is disordered in both structures. Changes in circular dichroism upon hirugen binding are therefore most likely the result of the flexibility associated with this loop. |
==Disease== | ==Disease== | ||
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==About this Structure== | ==About this Structure== | ||
| - | 1HGT is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Hirudo_medicinalis Hirudo medicinalis] and [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with SO3 as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Thrombin Thrombin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.21.5 3.4.21.5] Full crystallographic information is available from [http:// | + | 1HGT is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Hirudo_medicinalis Hirudo medicinalis] and [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=SO3:'>SO3</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Thrombin Thrombin], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.4.21.5 3.4.21.5] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1HGT OCA]. |
==Reference== | ==Reference== | ||
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[[Category: hydrolase(serine protease)]] | [[Category: hydrolase(serine protease)]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:01:06 2008'' |
Revision as of 11:01, 21 February 2008
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STRUCTURE OF THE HIRUGEN AND HIRULOG 1 COMPLEXES OF ALPHA-THROMBIN
Contents |
Overview
The isomorphous structures of the hirugen (N-acetylhirudin 53'-64' with sulfato-Tyr63') and hirulog 1 (D-Phe-Pro-Arg-Pro-(Gly)4 desulfato-Tyr63'-hirugen) complexes of human alpha-thrombin have been determined and refined at 2.2 A resolution to crystallographic R-factors of 0.167 and 0.163, respectively. The binding of hirugen to thrombin is similar to that of the binding of the C-terminal dodecapeptide of hirudin, including that of the terminal 3(10) helical turn. The sulfato Tyr63', which, as a result of sulfation, increases the binding affinity by an order of magnitude, is involved in an extended hydrogen bonding network utilizing all three sulfato oxygen atoms. The hirugen-thrombin complex is the first thrombin structure determined to have an unobstructed active site; this site is practically identical in positioning of catalytic residues and in its hydrogen bonding pattern with that of other serine proteinases. Hirulog 1, which is a poor thrombin substrate, is cleaved at the Arg3'-Pro4' bond in the crystal structure. The Arg3' of hirulog 1 occupies the specificity site, the D-Phe-Pro-Arg tripeptide is positioned like that of D-Phe-Pro-Arg chloromethylketone in the active site and the Pro4'(Gly)4 spacer to hirugen is disordered in the structure, as is the 3(10) turn of hirugen. The latter must be related to the simultaneous absence both of sulfation and of the last residue of hirudin (Gln65'). In addition, the autolysis loop of thrombin (Lys145-Gly150) is disordered in both structures. Changes in circular dichroism upon hirugen binding are therefore most likely the result of the flexibility associated with this loop.
Disease
Known diseases associated with this structure: Dysprothrombinemia OMIM:[176930], Hyperprothrombinemia OMIM:[176930], Hypoprothrombinemia OMIM:[176930]
About this Structure
1HGT is a Protein complex structure of sequences from Hirudo medicinalis and Homo sapiens with as ligand. Active as Thrombin, with EC number 3.4.21.5 Full crystallographic information is available from OCA.
Reference
Structure of the hirugen and hirulog 1 complexes of alpha-thrombin., Skrzypczak-Jankun E, Carperos VE, Ravichandran KG, Tulinsky A, Westbrook M, Maraganore JM, J Mol Biol. 1991 Oct 20;221(4):1379-93. PMID:1942057
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