1TOC

STRUCTURE OF SERINE PROTEINASE

DOI: 10.2210/pdb1TOC/pdb

Classification: COMPLEX (HYDROLASE/INHIBITOR)
Organism(s): Bos taurus, Ornithodoros moubata
Expression System: Escherichia coli
Mutation(s): No

Deposited: 1996-07-20 Released: 1997-07-23
Deposition Author(s): Van De Locht, A., Huber, R., Bode, W.

Experimental Data Snapshot

Method: X-RAY DIFFRACTION
Resolution: 3.10 Å
R-Value Work: 0.230
R-Value Observed: 0.230

wwPDB Validation 3D Report Full Report

This is version 1.2 of the entry. See complete history.

Literature

The ornithodorin-thrombin crystal structure, a key to the TAP enigma?

van de Locht, A., Stubbs, M.T., Bode, W., Friedrich, T., Bollschweiler, C., Hoffken, W., Huber, R.

(1996) EMBO J 15: 6011-6017

PubMed: 8947023 Search on PubMedSearch on PubMed Central
Primary Citation of Related Structures:
1TOC

PubMed Abstract:

Ornithodorin, isolated from the blood sucking soft tick Ornithodoros moubata, is a potent (Ki = 10(-12) M) and highly selective thrombin inhibitor. Internal sequence homology indicates a two domain protein. Each domain resembles the Kunitz inhibitor basic pancreatic trypsin inhibitor (BPTI) and also the tick anticoagulant peptide (TAP) isolated from the same organism. The 3.1 A crystal structure of the ornithodorin-thrombin complex confirms that both domains of ornithodorin exhibit a distorted BPTI-like fold. The N-terminal portion and the C-terminal helix of each domain are structurally very similar to BPTI, whereas the regions corresponding to the binding loop of BPTI adopt different conformations. Neither of the two 'reactive site loops' of ornithodorin contacts the protease in the ornithodorin-thrombin complex. Instead, the N-terminal residues of ornithodorin bind to the active site of thrombin, reminiscent of the thrombin-hirudin interaction. The C-terminal domain binds at the fibrinogen recognition exosite. Molecular recognition of its target protease by this double-headed Kunitz-type inhibitor diverges considerably from other members of this intensely studied superfamily. The complex structure provides a model to explain the perplexing results of mutagenesis studies on the TAP-factor Xa interaction.

Related Citations:

Two Heads are Better Than One: Crystal Structure of the Insect Derived Double Domain Kazal Inhibitor Rhodniin in Complex with Thrombin
Van De Locht, A., Lamba, D., Bauer, M., Huber, R., Friedrich, T., Kroger, B., Hoffken, W., Bode, W.
(1995) EMBO J 14: 5149

The Refined 1.9 A Crystal Structure of Human Alpha-Thrombin: Interaction with D-Phe-Pro-Arg Chloromethylketone and Significance of the Tyr-Pro-Pro-Trp Insertion Segment
Bode, W., Mayr, I., Baumann, U., Huber, R., Stone, S.R., Hofsteenge, J.
(1989) EMBO J 8: 3467

Organizational Affiliation:

Max-Planck-Institut für Biochemie, Abteilung Strukturforschung, Martinsreid, Germany.

Macromolecules

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(by identity cutoff) | Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
THROMBIN	A, D [auth C], G [auth E], J [auth G]	49	Bos taurus	Mutation(s): 0 Gene Names: F2 EC: 3.4.21.5
UniProt
Find proteins for P00735 (Bos taurus) Explore P00735 Go to UniProtKB: P00735
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Reference Sequence

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(by identity cutoff) | Structure

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
THROMBIN	B, E [auth D], H [auth F], K [auth H]	259	Bos taurus	Mutation(s): 0 Gene Names: F2 EC: 3.4.21.5
UniProt
Find proteins for P00735 (Bos taurus) Explore P00735 Go to UniProtKB: P00735
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Reference Sequence

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(by identity cutoff) | Structure

Entity ID: 3
Molecule	Chains	Sequence Length	Organism	Details	Image
ORNITHODORIN	C [auth R], F [auth S], I [auth T], L [auth U]	120	Ornithodoros moubata	Mutation(s): 0
UniProt
Find proteins for P56409 (Ornithodoros moubata) Explore P56409 Go to UniProtKB: P56409
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Reference Sequence