This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1sfq
From Proteopedia
| Line 1: | Line 1: | ||
[[Image:1sfq.gif|left|200px]] | [[Image:1sfq.gif|left|200px]] | ||
| - | + | <!-- | |
| - | + | The line below this paragraph, containing "STRUCTURE_1sfq", creates the "Structure Box" on the page. | |
| - | + | You may change the PDB parameter (which sets the PDB file loaded into the applet) | |
| - | + | or the SCENE parameter (which sets the initial scene displayed when the page is loaded), | |
| - | + | or leave the SCENE parameter empty for the default display. | |
| - | + | --> | |
| - | + | {{STRUCTURE_1sfq| PDB=1sfq | SCENE= }} | |
| - | + | ||
| - | + | ||
| - | }} | + | |
'''Fast form of thrombin mutant R(77a)A bound to PPACK''' | '''Fast form of thrombin mutant R(77a)A bound to PPACK''' | ||
| Line 37: | Line 34: | ||
[[Category: Pineda, A O.]] | [[Category: Pineda, A O.]] | ||
[[Category: Prasad, S.]] | [[Category: Prasad, S.]] | ||
| - | [[Category: | + | [[Category: Serine protease]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 08:38:41 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 05:38, 3 May 2008
Fast form of thrombin mutant R(77a)A bound to PPACK
Contents |
Overview
Na(+) binding near the primary specificity pocket of thrombin promotes the procoagulant, prothrombotic, and signaling functions of the enzyme. The effect is mediated allosterically by a communication between the Na(+) site and regions involved in substrate recognition. Using a panel of 78 Ala mutants of thrombin, we have mapped the allosteric core of residues that are energetically linked to Na(+) binding. These residues are Asp-189, Glu-217, Asp-222, and Tyr-225, all in close proximity to the bound Na(+). Among these residues, Asp-189 shares with Asp-221 the important function of transducing Na(+) binding into enhanced catalytic activity. None of the residues of exosite I, exosite II, or the 60-loop plays a significant role in Na(+) binding and allosteric transduction. X-ray crystal structures of the Na(+)-free (slow) and Na(+)-bound (fast) forms of thrombin, free or bound to the active site inhibitor H-d-Phe-Pro-Arg-chloromethyl-ketone, document the conformational changes induced by Na(+) binding. The slow --> fast transition results in formation of the Arg-187:Asp-222 ion pair, optimal orientation of Asp-189 and Ser-195 for substrate binding, and a significant shift of the side chain of Glu-192 linked to a rearrangement of the network of water molecules that connect the bound Na(+) to Ser-195 in the active site. The changes in the water network and the allosteric core explain the thermodynamic signatures linked to Na(+) binding and the mechanism of thrombin activation by Na(+). The role of the water network uncovered in this study establishes a new paradigm for the allosteric regulation of thrombin and other Na(+)-activated enzymes involved in blood coagulation and the immune response.
Disease
Known disease associated with this structure: Dysprothrombinemia OMIM:[176930], Hyperprothrombinemia OMIM:[176930], Hypoprothrombinemia OMIM:[176930]
About this Structure
1SFQ is a Protein complex structure of sequences from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Molecular dissection of Na+ binding to thrombin., Pineda AO, Carrell CJ, Bush LA, Prasad S, Caccia S, Chen ZW, Mathews FS, Di Cera E, J Biol Chem. 2004 Jul 23;279(30):31842-53. Epub 2004 May 19. PMID:15152000 Page seeded by OCA on Sat May 3 08:38:41 2008
