12486
Crystal structures of PcrB from Bacillus subtilis and Staphylococcus aureus in complex with ligands were solved , and together with site - directed mutagenesis and bioinformatics analyses , clearly reveal the catalytic mechanism of the enzyme .
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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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