Alignments of the cosB and TerS DNA packaging recognition elements of λ-like bacteriophages.

A. Alignment of R3 sequences of 21, Monarch, N15, and λ. Numbering is rightwards from the first base of the left cohesive end of each phage. Putative R3 sequences are highlighted in grey. The boundaries and locations of the R3 elements are only approximate and are mostly based on sequence conservation among the R3, R2 and R1 elements. Residues 56 and 59 in R3λ and R321 are important for recognition by TerS and are highlighted in green [56]. The CG→TA change at R3λ bp 58 (highlighted in green) renders λ IHF-dependent for plaque formation [49,70][62]. B. Alignments of the left ends of TerS subunits. Proposed recognition helixes are highlighted in grey and residues 20 and 24 of TerS21 and TerSλ, known to be involved in packaging recognition and discrimination, are highlighted in green.