American Society of Hirudotherapy

Structural model of an antistasin/notch-like fusion protein from the cocoon wall of the aquatic leech, Theromyzon tessulatum

Research article published in J Mol Model (2006)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Preclinical (animal)Genomics & ProteomicsSalivary PharmacologyMason TA et al. · J Mol Model, 2006

Abstract

The aquatic leech, Theromyzon tessulatum, secretes a proteinaceous cocoon with extraordinary physical properties (e.g., proteolytic, thermal resiliency). The deduced amino acid sequence of a major protein (Tcp-Theromyzon cocoon protein) from the T. tessulatum cocoon wall has been used to model the endogenous structure of the Tcp protein. The Tcp protein sequence comprises six internal repeats, each containing 12 ordered Cys residues. Amino acid alignments suggest that the region Cys1-->6 is homologous to antistasin, a leech anticoagulant, and Cys7-->12 is homologous to an epidermal growth factor-like domain found in notch-class proteins, which play critical roles in development, signaling, and adhesion throughout the Animalia. Modeling of individual domains (i.e., antistasin and notch) positions multiple hydrophobic and charged residues on the surface. When the antistasin and notch domains were fused, hydrophobic pockets appeared that may facilitate a polymerization mechanism. Collectively, the predicted features of our Tcp model are consistent with the physical properties of the leech cocoon wall.

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

Publication typeJournal ArticleResearch Support, U.S. Gov't, Non-P.H.S.
Indexed MeSH termsAnimalsAnticoagulantsBinding SitesInvertebrate HormonesLeechesModels, MolecularProtein ConformationReceptors, NotchRecombinant Fusion Proteins

Summary

The aquatic leech, Theromyzon tessulatum, secretes a proteinaceous cocoon with extraordinary physical properties (e.g., proteolytic, thermal resiliency).

Why This Matters for Hirudotherapy

This study presents a molecular model of Tcp (Theromyzon cocoon protein), a major structural protein from the cocoon wall of the aquatic leech Theromyzon tessulatum, based on deduced amino acid sequence analysis. The Tcp sequence contains six internal repeats with 12 ordered cysteine residues each; the Cys1→6 region shows homology to antistasin (a leech anticoagulant) and Cys7→12 to an EGF-like notch domain, with modeling suggesting hydrophobic pockets that may facilitate polymerization. For ASH, this is relevant as it concerns leech protein structural biology with antistasin-type anticoagulant domain homology. Caveat: This is a computational/modeling study of a cocoon structural protein from a non-medicinal leech species; no functional anticoagulant or therapeutic activity of Tcp itself is demonstrated.

Citation

Structural model of an antistasin/notch-like fusion protein from the cocoon wall of the aquatic leech, Theromyzon tessulatum.

Mason TA et al. · J Mol Model, 2006

DOI

Added to ASH library: May 27, 2026 · Site last updated: June 18, 2026

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