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Domain swapping in the sporulation response regulator Spo0A
R J Lewis1, K Muchová, J A Brannigan
1Structural Biology Laboratory Department of Chemistry, University of York, York, YO10 5DD, UK.
Journal of Molecular Biology
|March 25, 2000
Summary
Bacillus sporulation relies on Spo0A protein regulation. We determined the crystal structure of N-Spo0A, revealing a dimer formed by an alpha-helix swap, offering insights into signal transduction mechanisms.
Area of Science:
- Microbiology
- Structural Biology
- Biochemistry
Background:
- Microbial adaptive responses, like sporulation, are controlled by two-component systems.
- These systems involve sensor kinases and response regulators that mediate signal transduction via protein phosphorylation.
Purpose of the Study:
- To determine the crystal structure of the N-terminal receiver domain of Spo0A (N-Spo0A) from Bacillus stearothermophilus.
- To understand the structural basis of signal transduction and quaternary reorganization in N-Spo0A.
Main Methods:
- X-ray crystallography was used to determine the structure of N-Spo0A at 1.6 Å resolution.
- Structural comparison with phosphorylated N-Spo0A was performed.
Main Results:
- The crystal structure revealed N-Spo0A forms a dimer through an alpha-helix swap.
- Dimer formation is linked to cis-trans isomerization of the Lys106--Pro107 peptide bond.
- The observed dimer topology is similar to hypothetical CheY-like dimers.
Conclusions:
- The structural findings provide insights into the mechanism of signal transduction in Spo0A.
- The quaternary reorganization may impact active site stereochemistry and signaling.
- The structural similarity to CheY suggests evolutionary links within protein families.