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Method for Efficient Refolding and Purification of Chemoreceptor Ligand Binding Domain
Published on: December 12, 2017
Location and architecture of the Caulobacter crescentus chemoreceptor array
Ariane Briegel1, H Jane Ding, Zhuo Li
1Division of Biology, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125, USA.
Molecular Microbiology
|March 28, 2008
Summary
Researchers developed a new method to visualize bacterial cell structures. This technique revealed hexagonally packed chemoreceptor arrays near the flagellar motor in Caulobacter crescentus, providing insights into cell asymmetry.
Area of Science:
- Microbiology
- Structural Biology
- Cell Biology
Background:
- Chemoreceptors are crucial for bacterial sensing and motility.
- Understanding the spatial organization of chemoreceptors is key to deciphering cellular signaling pathways.
- Caulobacter crescentus serves as a model organism for studying bacterial development and asymmetry.
Purpose of the Study:
- To develop a novel method for simultaneously recording fluorescence and cryo-electron microscopy (cryo-EM) images of small bacterial cells.
- To identify and characterize the structural organization of chemoreceptor arrays in Caulobacter crescentus.
- To investigate the relationship between chemoreceptor arrays and the flagellar motor.
Main Methods:
- Development of a correlative imaging technique combining fluorescence microscopy and cryo-EM.
- Cryo-electron tomography (cryo-tomography) to visualize intact Caulobacter crescentus cells in a near-native state.
- 3D reconstruction and analysis of cryo-tomograms to determine the arrangement of chemoreceptors.
Main Results:
- Successfully identified chemoreceptor arrays in intact Caulobacter crescentus cells using the new method.
- Demonstrated that chemoreceptors are hexagonally packed with a 12 nm lattice spacing in wild-type cells.
- Observed chemoreceptor arrays located tens of nanometers from the flagellar motor, typically on the cell's convex side.
- Proposed a model where approximately 1000-2000 receptors form each array, consistent with known structural data.
Conclusions:
- The developed correlative imaging method is effective for studying the structure of small bacterial cells.
- Chemoreceptor arrays in Caulobacter crescentus exhibit precise hexagonal packing and are spatially organized relative to the flagellar motor.
- The findings support the understanding of Caulobacter crescentus's cellular asymmetry and sensory mechanisms.
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