The observation that TM4 Tmp mt3 is not essential for phage infection is consistent with the finding that the murein hydrolase activities of T4, T7, PRD1 and φ6 (Nakagawa et al., 1985; Moak and Molineux, 2000; Rydman and Bamford, 2000; Kanamaru et al., 2002) are also not required for infection. Here, EMP1 is linked to infection.