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Elastic Proteins May Have Originated in Cnidarians Such As the Fresh-Water Hydra with Its Stinging Spears; Over 500 Million G’s of Force Exerted in Hydra’s Spear Release
Scientists at Heidelberg University in Germany have discovered an unusually elastic protein in one of the most ancient groups of animals, the over 600-million-year-old cnidarians. The protein is a part of the “weapons system” that the cnidarians use: a kind of harpoon launched from their body at extremely high speed. The discovery of the hitherto unknown protein in the freshwater polyp Hydra suggests that the molecular mechanism of elasticity could have originated in the cnidarians and evolved to discharge a deadly weapon. Due to the similarity of the protein’s amino acid sequence to spidroin of spider silk, the researchers from the Centre for Organismal Studies dubbed the elastic protein “cnidoin.” The results of the research were published online on January 16, 2015 in BMC Biology. Elastomeric proteins evolved in a diverse range of animals and often fulfil highly specialized biological functions as, for eample, the elastin in the pulmonary alveoli of higher vertebrates, the resilin in the wing joints of insects, or the spidroin in the threads of spider silk. They give tissues mechanical properties that exceed those of artificial materials. These proteins, known as elastomers, share a common property – structurally disordered, repetitive protein sequences that store energy when a molecule is stretched which can then be used in the form of a movement after release. These movements can be rhythmical, as in the blood vessels leaving the heart, or they can be single, explosive movements, as in the jump of a grasshopper.