Nucleic Acids Research, 2005, Vol. 33, No. 19 6207 Figure 3. Sequencing reactions run alongside single strand labelled cleavage reactions to map (A) the SegH cleavage site, and (B) the Hef cleavage site. Note that the second gel is inverted to illustrate the cleavage sites on both strands. Sequence variation surrounding (C) the SegH cleavage site in some T-even-like phages with or without optional genes mobC or segH, and (D) the Hef cleavage site in T-even-like phages with and without optional genes mobE or hef. Figure 4. Competition between target sites for SegH and Hef endonucleases. (A) Purified SegH cleavage of target sites from T2 (triangles), T4 (squares) and LZ2 (circles). (B) Cleavage of T2 (triangles), T4 (squares) and U5 (circles) target sites by in vitro translated Hef. Open symbols denote incubations with twice as much endonuclease as in incubations denoted with closed symbols.