Amino acid sequence analysis of RepA proteins of RtTA1 plasmids.

<p>(A) Multiple alignment of N-terminal sequences of RepA/a-d. Identical amino acid residues were marked in yellow. (B) Secondary structure predictions of N-termini of individual RepA proteins. The regions constituting the α-helices responsible for RepA dimerization and helix-turn-helix (HTH) DNA binding domains were presented as blue cylinders and highlighted in grey.