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1bx8
From Proteopedia
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[[Image:1bx8.jpg|left|200px]] | [[Image:1bx8.jpg|left|200px]] | ||
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'''HIRUSTASIN FROM HIRUDO MEDICINALIS AT 1.4 ANGSTROMS''' | '''HIRUSTASIN FROM HIRUDO MEDICINALIS AT 1.4 ANGSTROMS''' | ||
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[[Category: Sheldrick, G M.]] | [[Category: Sheldrick, G M.]] | ||
[[Category: Uson, I.]] | [[Category: Uson, I.]] | ||
| - | [[Category: | + | [[Category: Anti-coagulant]] |
| - | [[Category: | + | [[Category: Conformational flexibility]] |
| - | [[Category: | + | [[Category: Peptidic inhibitor]] |
| - | [[Category: | + | [[Category: Serine protease inhibitor]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 12:04:19 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 09:04, 2 May 2008
HIRUSTASIN FROM HIRUDO MEDICINALIS AT 1.4 ANGSTROMS
Overview
BACKGROUND: Leech-derived inhibitors have a prominent role in the development of new antithrombotic drugs, because some of them are able to block the blood coagulation cascade. Hirustasin, a serine protease inhibitor from the leech Hirudo medicinalis, binds specifically to tissue kallikrein and possesses structural similarity with antistasin, a potent factor Xa inhibitor from Haementeria officinalis. Although the 2.4 A structure of the hirustasin-kallikrein complex is known, classical methods such as molecular replacement were not successful in solving the structure of free hirustasin. RESULTS: Ab initio real/reciprocal space iteration has been used to solve the structure of free hirustasin using either 1.4 A room temperature data or 1.2 A low temperature diffraction data. The structure was also solved independently from a single pseudo-symmetric gold derivative using maximum likelihood methods. A comparison of the free and complexed structures reveals that binding to kallikrein causes a hinge-bending motion between the two hirustasin subdomains. This movement is accompanied by the isomerisation of a cis proline to the trans conformation and a movement of the P3, P4 and P5 residues so that they can interact with the cognate protease. CONCLUSIONS: The inhibitors from this protein family are fairly flexible despite being highly cross-linked by disulphide bridges. This intrinsic flexibility is necessary to adopt a conformation that is recognised by the protease and to achieve an optimal fit, such observations illustrate the pitfalls of designing inhibitors based on static lock-and-key models. This work illustrates the potential of new methods of structure solution that require less or even no prior phase information.
About this Structure
1BX8 is a Single protein structure of sequence from Hirudo medicinalis. Full crystallographic information is available from OCA.
Reference
The 1.2 A crystal structure of hirustasin reveals the intrinsic flexibility of a family of highly disulphide-bridged inhibitors., Uson I, Sheldrick GM, de La Fortelle E, Bricogne G, Di Marco S, Priestle JP, Grutter MG, Mittl PR, Structure. 1999 Jan 15;7(1):55-63. PMID:10368273 Page seeded by OCA on Fri May 2 12:04:19 2008
