7541
Under axially imposed loads , several groups of proteins whose structure is dominated by alpha - helical coiled - coil structures can undergo unfolding transitions and secondary structure transformations , for example from coiled - coil alpha - helices to beta - sheet strands .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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