14347
Using magnetic beads with attached DNA containing the Escherichia coli lac operator , fusion proteins comprising the DNA-binding lac repressor could be affinity-purified and recovered by gentle elution conditions, such as with a lactose analogue or by enzymatic means using either deoxyribonuclease ( DNase ) or restriction endonucleases .
 ( protein: DNase, None) , ( DNA: DNA, None) , ( protein: deoxyribonuclease, None) , ( protein: restriction endonucleases, None) , ( protein: fusion proteins, None) , ( DNA: DNA-binding lac repressor, None) , ( DNA: Escherichia coli lac operator, None) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: RNA,cell type,protein,cell line,DNA, Arguments type: . 
Text: {0} 
Answer:
 ( protein: DNase, None) , ( DNA: DNA, None) , ( protein: deoxyribonuclease, None) , ( protein: restriction endonucleases, None) , ( protein: fusion proteins, None) , ( DNA: DNA-binding lac repressor, None) , ( DNA: Escherichia coli lac operator, None) 