The H101R and A98P allelesare likely to alter the response to signals promoting sporulation. Aspo0F(H101A) allele results in a sporulation-proficient strain that throws off sporulation-deficient papillae [48] , and the same mutation has been shown to suppress the spo 2 phenotype of a strain containing a defective kinA allele. H101 has been proposed as a potential metal-binding site with particular affinity for Cu 2+ [49] . Binding of Cu 2+ (or another divalent metal) at this site may modulate interaction with one or more sensor kinases that promote sporulation. Substitution of positively charged arginine at this position could potentially mimic the binding of a metal cation in the loop containing H101, resulting in altered sporulation of the strains due to a change in the interaction with the kinases governing sporulation. It is unclear why, given the proposed role of divalent Cu 2+ in suppressing sporulation, H101R would result in a hypersporulation phenotype. The mechanistic relationship between spo0F(H101R) and the hypersporulation phenotype will be tested in future experiments.