10868
Here , we identify a Zn (2) + - driven N - terminal to C - terminal tertiary interaction in PrP ( C ) .
 Zn (2) +, N, C
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 Zn (2) +, N, C