Self-assembling proteins compose the chemically resistant shell biomaterial of planktonic tintinnid ciliates

peer-reviewed · Nature Communications · 2026

peer-reviewed · Nature Communications · 2026. Maximilian H. Ganser et al. Biomaterials provide superior properties and sustainable alternatives relevant to medicine, textiles, and…
Date 2026-06-13
Type peer-reviewed
Venue Nature Communications
Publisher Springer Science and Business Media LLC
Contribution downstream-application
DOI 10.1038/s41467-026-74402-4
Citations (OpenAlex) 1
Venue 2-year citedness 17.60

Abstract

Biomaterials provide superior properties and sustainable alternatives relevant to medicine, textiles, and high-tech applications. Research has mainly focused on animal-derived proteinaceous biomaterials, which remain challenging to reproduce while retaining their remarkable properties. Here, we show that the shell biomaterial of tintinnid ciliates, a lineage of planktonic unicellular eukaryotes, is composed of self-assembling structural proteins. The shells form in sea- and freshwater, are structurally diverse, and exhibit resistance against high temperatures and the strongest chemicals. Combining single-cell transcriptomics with proteomics of the shells, we identify the amino acid sequences of the shell-forming proteins that represent a new family unique to tintinnid ciliates, which we term Tintinnidorin. The proteins are rich in aromatic residues and possess a coherent architecture with flexible, unfolded segments connecting a folded core structure of beta-sheets. These multivalent capabilities facilitate intracellular storage, extracellular self-assembly, wet adhesion, thermostability, and salt tolerance. Tintinnid ciliates and their Tintinnidorin proteins provide an accessible system to elucidate sequence-structure-material relationships and inspire biomaterial design.

Authors

  1. Maximilian H. Ganser · University of Salzburg
  2. Markus Wiederstein · University of Salzburg
  3. Christof Regl · University of Salzburg
  4. Laura A. Katz · Smith College
  5. Sabine Agatha · University of Salzburg

Methods and tools

  • Tintinnid ciliate shell proteins (Tintinnidorin): Combines Casanovo de novo sequencing of shell proteomes, Stitch assembly and single-cell transcriptomics to identify Tintinnidorin, a new family of self-assembling proteins forming the chemically resistant shells of tintinnid ciliates.

Methods it uses

  • Casanovo: First Transformer
  • Stitch: Assembles de novo peptides from Casanovo, PEAKS, pNovo and MaxNovo into full antibody sequences, and corrects the two error classes that assembly alone cannot: mass coincidences, where a different residue combination matches the same mass, and I/L ambiguity.

Data deposited

  • Shell composition of the marine planktonic ciliate Schmidingerella (Alveolata, Ciliophora, Oligotrichea) — as deposited · PXD070957

Cites (2)

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