1TWX: Crystal Structure Of The Thrombin Mutant D221a/d222k

Citation:
Abstract
The thrombin mutant D221A/D222K (ARK) does not bind Na+ and has interesting functional properties intermediate between those of the slow and fast forms of wild type. We solved the X-ray crystal structure of ARK bound at exosite I with a fragment of hirudin at 2.4-A resolution. The structure shows a slight collapse of the 186 and 220 loops into the Na+ binding site due to disruption of the Asp222:Arg187 ion-pair. The backbone O atoms of Arg221a and Lys224 are shifted into conformations that eliminate optimal interaction with Na+. A paucity of solvent molecules in the Na+ binding site is also noted, by analogy to what is seen in the structure of the slow form. These findings reinforce the crucial role of the Asp222:Arg187 ion-pair in stabilizing the fast form of thrombin.
PDB ID: 1TWXDownload
MMDB ID: 51579
PDB Deposition Date: 2004/7/1
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 2.4  Å
Source Organism:
synthetic construct
Similar Structures:
Biological Unit for 1TWX: trimeric; determined by author
Molecular Components in 1TWX
Label Count Molecule
Proteins (3 molecules)
1
Prothrombin(Gene symbol: F2)
Molecule annotation
1
Prothrombin(Gene symbol: F2)
Molecule annotation
1
Hirudin
Molecule annotation
Chemical (1 molecule)
1
1
* Click molecule labels to explore molecular sequence information.

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