5093
Sequence comparisons of prokaryotic RCR initiators has revealed a set of three common motifs , two of which , a putative metal coordination site and a downstream active - site tyrosine motif , could be tentatively identified in parvoviral replicator proteins .
 prokaryotic RCR initiators, parvoviral replicator proteins
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 prokaryotic RCR initiators, parvoviral replicator proteins