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The variant Id-3L protein is functionally distinguishable from conventional Id-3 since in in vitro DNA mobility shift assays , it was greatly impaired in its ability to abrogate binding of the basic helix-loop-helix protein , E47 , to an E box recognition sequence .
 helix-loop-helix protein, E47, Id-3, E box recognition sequence, Id-3L protein
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 helix-loop-helix protein, E47, Id-3, E box recognition sequence, Id-3L protein