23337
A His - tag was cloned at the N - terminus , along with R403Q , to facilitate isolation of myosin subfragment - 1 ( S1 ) .
 Chemical: His; Chemical: N
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: His; Chemical: N