1LDT image
Entry Detail
PDB ID:
1LDT
Title:
COMPLEX OF LEECH-DERIVED TRYPTASE INHIBITOR WITH PORCINE TRYPSIN
Biological Source:
Source Organism:
PDB Version:
Deposition Date:
1997-05-15
Release Date:
1998-05-20
Method Details:
Experimental Method:
Resolution:
1.90 Å
R-Value Work:
0.19
R-Value Observed:
0.19
Space Group:
P 43 21 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:TRYPTASE INHIBITOR
Chain IDs:B (auth: L)
Chain Length:46
Number of Molecules:1
Biological Source:Hirudo medicinalis
Polymer Type:polypeptide(L)
Description:TRYPSIN
Chain IDs:A (auth: T)
Chain Length:223
Number of Molecules:1
Biological Source:Sus scrofa
Ligand Molecules
Primary Citation
The three-dimensional structure of recombinant leech-derived tryptase inhibitor in complex with trypsin. Implications for the structure of human mast cell tryptase and its inhibition.
J.Biol.Chem. 272 19931 19937 (1997)
PMID: 9242660 DOI: 10.1074/jbc.272.32.19931

Abstact

The x-ray crystal structure of recombinant leech-derived tryptase inhibitor (rLDTI) has been solved to a resolution of 1.9 A in complex with porcine trypsin. The nonclassical Kazal-type inhibitor exhibits the same overall architecture as that observed in solution and in rhodniin. The complex reveals structural aspects of the mast cell proteinase tryptase. The conformation of the binding region of rLDTI suggests that tryptase has a restricted active site cleft. The basic amino terminus of rLDTI, apparently flexible from previous NMR measurements, approaches the 148-loop of trypsin. This loop has an acidic equivalent in tryptase, suggesting that the basic amino terminus could make favorable electrostatic interactions with the tryptase molecule. A series of rLDTI variants constructed to probe this hypothesis confirmed that the amino-terminal Lys-Lys sequence plays a role in inhibition of human lung tryptase but not of trypsin or chymotrypsin. The location of such an acidic surface patch is in accordance with the known low molecular weight inhibitors of tryptase.

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Primary Citation of related structures