ORF43 from the complete sequence of SMP was analyzed. (A) Location of LySMP (ORF42) and HolSMP (ORF43), which are likely to comprise the putative holin-lysin lysis system of SMP. (B) The primary sequence of the HolSMP product. Charged residues are indicated below the sequence. (C) Secondary structure of HolSMP predicted by SOSUI.