ClustalW alignments of regulatory and catalytic proteins in heptaprenyl and hexaprenyl diphosphate synthase heterodimers. a) S. aureus, S. epidermidis, S. haemolyticus, S. pneumoniae, B. subtilis, and M. luteus HepPPS-1 and HexPPS-1 sequences. Conserved residues in the interface of the two subunits are shown in orange. This is the regulatory protein. b) S. aureus, S. epidermidis, S. haemolyticus, S. pneumoniae, B. subtilis, and M. luteus HepPPS-2 and HexPPS-2 sequences. Conserved residues at the interface of the two subunits are shown in orange. This is the protein that contains the Asp-rich domains involved in catalysis.