Fig. 6

Neighbor-joining tree of large terminase proteins. This tree was generated by ClustalX [13], displayed in Mega6 [40], and contains large terminase sequences from phages with experimentally determined packaging mechanisms and physical ends (see Additional file 1). Bootstrap values are for 1000 trials. The scale bar shows 0.1 amino acid substitutions per site. We manually assigned clusters in Phamerator that correspond to packaging strategies. For example, phages that use 3’ cos ends (HK97) are assigned to cluster A1. This phylogenetic tree indicates that large terminase proteins sharing phamilies and packaging strategies also clade together