A Kazal-type inhibitor with thrombin specificity from Rhodnius prolixus.
J Biol Chem
; 268(22): 16216-22, 1993 Aug 05.
Article
in En
| MEDLINE
| ID: mdl-8344906
ABSTRACT
A thrombin-specific inhibitor with an apparent molecular mass of 11 kDa has been purified from the insect Rhodnius prolixus. Amino-terminal protein sequence analysis allowed the molecular cloning of the corresponding cDNA. The open reading frame codes for a protein of about 103 amino acid residues and displays an internal sequence homology of residues 6-48 with residues 57-101 indicating a two-domain structure. Based on the amino acid sequence the two domains exhibit high homology to protease inhibitors belonging to the Kazal-type family. Model building suggests that the first domain binds to the active site with residue His10 pointing into the specificity pocket. From gel filtration and tight-binding inhibition experiments the inhibitor appears to form 11 complexes with thrombin. Periplasma-directed heterologous expression of the rhodniin cDNA in Escherichia coli yields the intact thrombin inhibitor. Natural and recombinant rhodniin both display inhibition constants of about 2 x 10(-13) M.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Rhodnius
/
Thrombin
/
Insect Proteins
/
Insect Hormones
Limits:
Animals
Language:
En
Journal:
J Biol Chem
Year:
1993
Document type:
Article
Affiliation country:
Germany