9RT6

Structure of synthetic C-terminal biotinylated schistosomin with the point mutation D88E from Biomphalaria glabrata in P21 space group

Replaces:  9FDM

Summary for 9RT6

• Entry DOI: 10.2210/pdb9rt6/pdb
• Descriptor: Schistosomin, BIOTIN, SULFATE ION, ... (4 entities in total)
• Functional Keywords: toxin
• Biological source: Biomphalaria glabrata (Bloodfluke planorb, Freshwater snail)
• Total number of polymer chains: 2
• Total formula weight: 18658.88

Authors

Morera, S.,Vigouroux, A. (deposition date: 2025-07-02, release date: 2025-07-23, Last modification date: 2026-09-09)

Primary citation

Melnyk, O.,Caby, S.,Vigouroux, A.,Demanche, C.,Desmet, R.,Senechal, M.,Snella, B.,Mougel, A.,Boidin-Wichlacz, C.,Parmentier, A.,Pasco, U.,Cantel, S.,Morera, S.,Vicogne, J.
Total synthesis and structural characterization of a novel protein scaffold from the snail Biomphalaria glabrata.
Protein Sci., 35:e70745-e70745, 2026

PubMed Abstract: Disulfide-rich miniproteins constitute compact and highly stable scaffolds of growing interest for molecular and structural engineering. Schistosomins are ~80-residue proteins conserved across gastropods that form a long-standing orphan family whose structure and biological roles have remained unknown. Here, we report the total chemical synthesis and structural characterization of a schistosomin isoform from Biomphalaria glabrata, a medically relevant intermediate host of the parasite Schistosoma mansoni. Using state-of-the-art solid-phase peptide synthesis, chemoselective peptide ligation, and controlled oxidative folding, we obtained homogeneous, well-folded schistosomin suitable for biophysical and structural studies. High-resolution X-ray crystallography reveals a previously undescribed disulfide-rich fold defining a new class of miniprotein scaffold. Nano differential scanning fluorimetry and circular dichroism experiments demonstrate the remarkable thermal stability of this scaffold. Complementary in silico analyses suggest that the two naturally occurring isoforms, which differ by a single residue, exhibit highly similar structural and dynamic properties. Finally, transcript and protein analyses across snail tissues provide the first spatial expression map of schistosomin in a medically relevant mollusk. Together, this work establishes schistosomin as a novel and robust miniprotein scaffold and provides a structural and biological framework for exploring its function and potential applications.

PubMed: 42554520
DOI: 10.1002/pro.70745

Experimental method

X-RAY DIFFRACTION (1.897 Å)