Function of the SpoVAEa and SpoVAF Proteins of Bacillus subtilis Spores.

摘要

The Bacillus subtilis spoVAEa and spoVAF genes are expressed in developng spores as members of the spoVA operon that encodes proteins essential for the uptake and release of dipicolinic acid (DPA) during spore formation and germination. We now show that: 1) spoVAEa and spoVAF genes are present in many but not all members of the order Bacillales; 2) the SpoVAEa amino acid sequence is well conserved in those species that express this protein; 3) SpoVAEa is present on the outer surface of the inner membrane of dormant spores, where previous work has shown that SpoVAD is located; 4) SpoVAEa and SpoVAD are distributed similarly in fractions of disrupted spores, although SpoVAEa levels are only ~ 15% of thiose of SpoVAD; 5) loss of SpoVAF or both SpoVAEa and SpoVAF had no effect on sporulation of DPA accumulation by spores; 6) spores lacking SpoVAF or both SpoVAEa and SpoVAF germinated normally with germinant receptor-independent germinants, but slower than wild-type spres with germinant receptor-dependent germinants; and 7) the germination phenotype of spores lacking SpoVAF or SpoVAEa and SpoVAF was complemented by ectopic co-expression of the missing proteins.