Functional phage display of leech-derived tryptase inhibitor (LDTI): construction of a library and selection of thrombin inhibitors

The recombinant phage antibody system pCANTAB 5E has been used to display functionally active leech-derived tryptase inhibitor (LDTI) on the tip of the filamentous M13 phage. A limited combinatorial library of 5.2 x 10(4) mutants was created with a synthetic LDTI gene, using a degenerated oligonucleotide and the pCANTAB 5E phagemid. The mutations were restricted to the P1-P4' positions of the reactive site. Fusion phages and appropriate host strains containing the phagemids were selected after binding to thrombin and DNA sequencing. The variants LDTI-2T (K8R, I9V, S10, K11W, P12A), LDTI-5T (K8R, I9V, S10, K11S, P12L) and LDTI-10T (K8R, I9L, S10, K11D, P12I) were produced with a Saccharomyces cerevisiae expression system. The new inhibitors, LDTI-2T and -5T, prolong the blood clotting time, inhibit thrombin (Ki 302 nM and 28 nM) and trypsin (Ki 6.4 nM and 2.1 nM) but not factor Xa, plasma kallikrein or neutrophil elastase. The variant LDTI-10T binds to thrombin but does not inhibit it. The relevant reactive site sequences of the thrombin inhibiting variants showed a strong preference for arginine in position P1 (K8R) and for valine in P1' (I9V). The data indicate further that LDTI-5T might be a model candidate for generation of active-site directed thrombin inhibitors and that LDTI in general may be useful to generate specific inhibitors suitable for a better understanding of enzyme-inhibitor interactions.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Phage display of the leech-derived tryptase inhibitor LDTI produced variants LDTI-2T and LDTI-5T that inhibit thrombin (Ki 302 and 28 nM) and prolong clotting, with LDTI-5T proposed as a model for active-site-directed thrombin inhibitors.

Explore how this research connects to clinical practice

More peer-reviewed studies in Drug Development.

• Hirudotherapy in Medicine and Dentistry — Jha K et al. (2015)
• Leech therapy: a history — Hyson J (2005)
• Hirudins of the Asian medicinal leech, Hirudinaria manillensis: same same, but different — Lukas P et al. (2019)
• Transcriptomic analysis of the salivary gland of medicinal leech Hirudo nipponia — Lu Z et al. (2018)
• Molecular dynamic and pharmacological studies on protein-engineered hirudin variants of Hirudinaria manillensis and Hirudo medicinalis — Sun Y et al. (2022)
• Cell-free synthesis of the hirudin variant 1 of the blood-sucking leech Hirudo medicinalis — Wüstenhagen D et al. (2020)
• Hirudin variants production by genetic engineered microbial factory — Zhang J, Lan N (2018)
• Hirudin in heparin-induced thrombocytopenia — Lubenow N, Greinacher A (2002)
• Hirudin ameliorates diabetic nephropathy by inhibiting Gsdmd-mediated pyroptosis — Han J et al. (2023)
• Hirudin as alternative anticoagulant--a historical review — Markwardt F (2002)

Browse all ASH-analysed research →