Abstract
Spore formation is an extreme response of many bacterial species to starvation. In the case of pathogenic species of Bacillus and Clostridium, it is also a component of disease transmission. Entry into the pathway of sporulation in Bacillus subtilis and its relatives is controlled by an expanded two-component system in which starvation signals lead to the activation of sensor kinases and phosphorylation of the master sporulation response regulator Spo0A. Accumulation of threshold concentrations of Spo0A similar to P heralds the commitment to sporulation. Countering the activities of the sensor kinases are phosphatases such as Spo0E, which dephosphorylate Spo0A similar to P and inhibit sporulation. Spo0E-like protein-aspartic acid-phosphate phosphatases, consisting of 50-90 residues, are conserved in sporeforming bacteria and unrelated in sequence to proteins of known structure. Here we determined the structures of the Spo0A similar to P phosphatases BA1655 and BA5174 from Bacillus anthracis using nuclear magnetic resonance spectroscopy. Each is composed of two anti-parallel alpha-helices flanked by flexible regions at the termini. The signature SQELD motif (SRDLD in BA1655) is situated in the middle of helix alpha 2 with its polar residues projecting outward. BA5174 is a monomer, whereas BA1655 is a dimer. The four-helix bundle structure in the dimer is reminiscent of the phosphotransferase Spo0B and the chemotaxis phosphatase CheZ, although in contrast to these systems, the subunits in BA1655 are in head-to-tail rather than head-to-head apposition. The implications of the structures for interactions between the phosphatases and their substrate Spo0A similar to P are discussed.
Original language | English |
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Pages (from-to) | 37993-38003 |
Number of pages | 11 |
Journal | Journal of Biological Chemistry |
Volume | 281 |
Issue number | 49 |
DOIs | |
Publication status | Published - 8 Dec 2006 |
Keywords
- TRANSCRIPTION FACTOR SPO0A
- TORSION ANGLE DYNAMICS
- RESPONSE REGULATOR
- MOLECULAR RECOGNITION
- SUBTILIS SPORULATION
- HISTIDINE KINASES
- ESCHERICHIA-COLI
- PHOSPHORELAY
- ASSIGNMENT
- MECHANISM