6758
Sequence conservation is greatest for residues located near the active centers of the exo and pol domains of the E . coli DNA polymerase I structure .
 exo, pol domains, E . coli DNA polymerase I
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 exo, pol domains, E . coli DNA polymerase I