Regulation of phosphoglycerate mutase in developing forespores and dormant spores ofBacillus megaterium by thein vivo levels of phosphoglycerate mutase inhibitor

Bacillus megaterium accumulated 3-phosphoglycerate during sporulation which was utilized during spore germination. During sporulation a protein was synthesized before or at the start of 3-phosphoglycerate accumulation inside the developing spores about 1.5 h before dipicolinic acid accumulation. This protein has an affinity for Mn²⁺ and other divalent metal ions and inhibits phosphoglycerate mutase activity which has been shown to require Mn²⁺ However, the levels of the inhibitor decreased considerably (75–85%) during spore germination. No appreciable amount of the inhibitor was detected in the vegetable cell and mother cell compartment; however, the forespore compartment possesses an activity comparable to that of dormant spores. The partially purified inhibitor has a molecular weight of 11,000 and possesses both high and low affinity binding sites for Mn²⁺ and Ca²⁺ as determined by Scatchard plot analysis.