Spo0A of C. difficile Strain 630Derm Contains a 6aminoacid Duplication BLAST homology searches readily identify a homolog of the well-characterized B. subtilis Spo0A protein in C. difficile 630 (CD1214) and previous work demonstrated that a spo0A mutant (an insertional inactivation of cd1214) -as expected -no longer forms spores [41] . In silico analyses suggest a similar secondary structure for both proteins ( Fig. 2A) , with a conserved dimerization and DNA binding domain, separated by a poorly conserved hinge region [7, 12] .