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A family of textilinin genes, two of which encode proteins with antihaemorrhagic properties
Author(s) -
Filippovich Igor,
Sorokitasha,
Masci Paul P.,
De Jersey John,
Whitaker Alan N.,
Winzor Donald J.,
Gaffney Patrick J.,
Lavin Martin F.
Publication year - 2002
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1046/j.1365-2141.2002.03878.x
Subject(s) - plasmin , aprotinin , serine protease , peptide , amino acid , protein precursor , complementary dna , biology , peptide sequence , biochemistry , recombinant dna , microbiology and biotechnology , fusion protein , thrombin , gene , protease , medicine , enzyme , platelet , immunology , surgery
Summary. Two peptides, textilinins 1 and 2, isolated from the venom of the Australian common brown snake, Pseudonaja textilis textilis, are effective in preventing blood loss. To further investigate the potential of textilinins as antihaemorrhagic agents, we cloned cDNAs encoding these proteins. The isolated full‐length cDNA (430 bp in size) was shown to code for a 59 amino acid protein, corresponding in size to the native peptide, plus an additional 24 amino acid propeptide. Six such cDNAs were identified, differing in nucleotide sequence in the coding region but with an identical propeptide. All six sequences predicted peptides containing six conserved cysteines common to Kunitz‐type serine protease inhibitors. When expressed as glutathione S‐transferase (GST) fusion proteins and released by cleavage with thrombin, only those peptides corresponding to textilinin 1 and 2 were active in inhibiting plasmin with K i values similar to those of their native counterparts and in binding to plasmin less tightly than aprotinin by two orders of magnitude. Similarly, in the mouse tail vein blood loss model only recombinant textilinin 1 and 2 were effective in reducing blood loss. These recombinant textilinins have potential as therapeutic agents for reducing blood loss in humans, obviating the need for reliance on aprotinin, a bovine product with possible risk of transmissible disease, and compromising the fibrinolytic system in a less irreversible manner.