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High-throughput Crystallization of Membrane Proteins Using the Lipidic Bicelle Method
Published on: January 9, 2012
Cyclopropane ring formation in membrane lipids of bacteria
1Department of Biological Sciences, University of Cincinnati, Ohio 45221-0006, USA.
Microbiology and Molecular Biology Reviews : MMBR
|December 31, 1997
Summary
Cyclopropane fatty acids (CFAs) are formed by a unique bacterial enzyme that modifies membrane phospholipids. Despite their widespread presence, the physiological role of CFAs remains unclear.
Area of Science:
- Microbiology
- Biochemistry
- Molecular Biology
Background:
- Cyclopropane fatty acids (CFAs) are found in bacterial phospholipids, formed by methylene addition to unsaturated fatty acids.
- CFA synthesis occurs post-translationally on mature phospholipids within membrane bilayers, typically at the onset of stationary phase.
Purpose of the Study:
- To investigate the biosynthesis, regulation, and physiological role of cyclopropane fatty acids (CFAs) in bacteria.
- To characterize the enzyme responsible for CFA formation, CFA synthase, and its unique catalytic mechanism.
Main Methods:
- Genetic manipulation of Escherichia coli to study CFA synthase regulation and function.
- Purification and molecular analysis of the CFA synthase enzyme.
- Biochemical assays to assess enzyme specificity and protein-lipid interactions.
Main Results:
- Identified the CFA synthase gene as rpoS-regulated in E. coli.
- Demonstrated that CFA synthase acts on membrane-bound phospholipids, not free fatty acids.
- Purified the unstable CFA synthase, revealing novel protein-lipid interactions and identifying related enzymes in pathogens.
Conclusions:
- CFA biosynthesis involves unique enzymatic mechanisms and protein-lipid interactions within bacterial membranes.
- Genetic studies in E. coli provide tools to evaluate proposed cellular functions of CFAs.
- Characterization of CFA synthase has implications for understanding bacterial physiology and identifying enzymes in pathogens.
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