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Keywords:

Bacillus subtilis, Bacterial Proteins, Ca(2+)-Transporting ATPase, Calcium, Calcium Channels, P-Type, Calcium Signaling, Chelating Agents, Gene Expression Regulation, Bacterial, Immunohistochemistry, Molecular Sequence Data, Mutation, Sequence Homology, Amino Acid, Sequence Homology, Nucleic Acid, Spores, Bacterial, Science & Technology, Life Sciences & Biomedicine, Cell Biology, COMPLETE GENOME SEQUENCE, SARCO/ENDOPLASMIC RETICULUM, SARCOPLASMIC-RETICULUM, INDUCED GERMINATION, ESCHERICHIA-COLI, CALCIUM-PUMP, GENE, SPORES, CA2+-ATPASE, ANTIPORTER, Calcium-Transporting ATPases, Sarcoplasmic Reticulum Calcium-Transporting ATPases, 0601 Biochemistry and Cell Biology, 0606 Physiology, 1116 Medical Physiology, Biochemistry & Molecular Biology, 3101 Biochemistry and cell biology, 3208 Medical physiology

Abstract:

The open reading frame designated yloB in the genomic sequence of Bacillus subtilis encodes a putative protein that is most similar to the typically eukaryotic type IIA family of P-type ion-motive ATPases, including the endo(sarco)plasmic reticulum (SERCA) and PMR1 Ca(2+)-transporters, located respectively in the SERCA and the Golgi apparatus. The overall amino acid sequence is more similar to that of the Pmr1s than to the SERCAs, whereas the inverse is seen for the 10 amino acids that form the two Ca(2+)-binding sites in SERCA. Sporulating but not vegetative B. subtilis cells express the predicted protein, as shown by Western blotting and by the formation of a Ca(2+)-dependent phosphorylated intermediate. Half-maximal activation of phosphointermediate formation occurred at 2.5 microM Ca(2+). Insertion mutation of the yloB gene did not affect the growth of vegetative cells, did not prevent the formation of viable spores, and did not significantly affect 45Ca accumulation during sporulation. However, spores from knockouts were less resistant to heat and showed a slower rate of germination. It is concluded that the P-type Ca(2+)-transport ATPase from B. subtilis is not essential for survival, but assists in the formation of resistant spores. The evolutionary relationship of the transporter to the eukaryotic P-type Ca(2+)-transport ATPases is discussed.