This sequence differs slightly from the consensus sequence for Pribnow box (TATAAT) described in the previous topic, where it was shown that among prokaryotes the range of conservation of bases varies from 45% to 96%. There are other common sequences located at -30 and -60 bases (upstream), the latter being CAP site, which is marked by an interrupted three base pair inverted repeat, flanked by non-inverted T-A base pair on either side as follows.
This CAP binding site is common to lac,gal and ara operons. It lies within -53 to -23 bp in gal operon,bctween -72 to -52bp in lac operon and between -107 to -78bp in ara operon.
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