Conservation of ClpX/ClpP. Multiple-sequence alignment of ClpP (A) and ClpX (B) sequences from E. coli (Ec), S. aureus (Sa), and B. anthracis (Ba) was performed using the ClustalW program. The residues important for catalytic activity of ClpP are shown in bold. B. anthracis has at least two ClpP genes which are designated 1 and 2. *, amino acids are identical; colons, amino acids have conserved substitutions; periods, amino acids have semiconserved substitutions.