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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, RESULTS. Meshes: Amino Acid Sequence, Animals, Blotting, Western, Collagen, Elasticity, Elastomers, Gene Expression Regulation, Hydra, Hydrophobic and Hydrophilic Interactions, Immunohistochemistry, Microscopy, Atomic Force, Molecular Dynamics Simulation, Molecular Sequence Data, Nematocyst, Protein Aggregates, Protein Structure, Tertiary, Recombinant Proteins, Silk, Time Factors.
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Does a fast recoiling silk-like elastomer facilitate nanosecond nematocyst discharge? Context: The discharge of the Cnidarian stinging organelle, the nematocyst, is one of the fastest processes in biology and involves volume changes of the highly pressurised (150 bar) capsule of up to 50%. Hitherto, the molecular basis for the unusual biomechanical properties of nematocysts has been elusive, as their structure was mainly defined as a stress-resistant collagenous matrix. Here, we characterise Cnidoin, a novel elastic protein identified as a structural component of Hydra nematocysts. Cnidoin is expressed in nematocytes of all types and immunostainings revealed incorporation into capsule walls and tubules concomitant with minicollagens. Similar to spider silk proteins, to which it is related at sequence level, Cnidoin possesses high elasticity and fast coiling propensity as predicted by molecular dynamics simulations and quantified by force spectroscopy. Recombinant Cnidoin showed a high tendency for spontaneous aggregation to bundles of fibrillar structures.
assistant
Cnidoin represents the molecular factor involved in kinetic energy storage and release during the ultra-fast nematocyst discharge. Furthermore, it implies an early evolutionary origin of protein elastomers in basal metazoans. Final Decision: yes