3919
Based around the common AKR fold of ( beta / alpha ) 8 barrel with two additional alpha - helices , the E . coli AKRs have a loop structure that is more diverse than their mammalian counterparts , creating a variety of active site architectures .
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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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