Genotype, Phenotype, and Protein Structure in a Regulator of Sporulation: Effects of Mutations in the spoIIAA Gene of Bacillus subtilis

SpoIIAA, a phosphorylatable protein, is essential to the regulation of ς(F), the first sporulation-specific transcription factor of Bacillus subtilis. The solution structure of SpoIIAA has recently been published. Here we examine four mutant SpoIIAA proteins and correlate their properties with the phenotypes of the corresponding B. subtilis mutant strains. Two of the mutations severely disrupted the structure of the protein, a third greatly diminished the rate of its phosphorylation and abolished dephosphorylation, and the fourth left phosphorylation unaffected but reduced the rate of dephosphorylation about 10-fold.

SpoIIAA是一种可磷酸化蛋白，对枯草芽孢杆菌（Bacillus subtilis）的首个孢子特异性转录因子σ^F的调控至关重要。SpoIIAA的溶液结构已于近期发表。本研究针对四种突变型SpoIIAA蛋白展开分析，并将其特性与对应枯草芽孢杆菌突变菌株的表型相关联。其中两种突变会严重破坏该蛋白的空间结构；第三种突变可大幅降低其磷酸化速率并完全阻断去磷酸化过程；第四种突变对磷酸化过程无影响，但可使去磷酸化速率降低约10倍。