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The initial fragment hits were thoroughly validated biophysically by isothermal titration calorimetry ( ITC ) and NMR techniques and observed by X - ray crystallography to bind in a shallow surface pocket that is occupied in the native complex by the side chain of a phenylalanine from the conserved FxxA interaction motif found in BRCA2 .
 Chemical: phenylalanine
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: phenylalanine