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Method to Visualize and Analyze Membrane Interacting Proteins by Transmission Electron Microscopy
Published on: March 5, 2017
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Fluorinated Aromatic Amino Acids Distinguish Cation-π Interactions from Membrane Insertion
Tao He1, Anne Gershenson2, Stephen J Eyles2
1From the Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467.
The Journal of Biological Chemistry
|June 21, 2015
Summary
Fluorinated amino acids experimentally distinguish protein cation-π interactions from membrane insertion. This method identifies aromatic residues crucial for peripheral membrane protein function.
Area of Science:
- Biochemistry
- Structural Biology
- Protein-Lipid Interactions
Background:
- Cation-π interactions are proposed binding modes for peripheral membrane proteins.
- Differentiating cation-π interactions from hydrophobic membrane insertion of aromatic residues is challenging.
Purpose of the Study:
- To develop a method to experimentally distinguish cation-π interactions from membrane insertion.
- To identify specific aromatic residues involved in phosphatidylcholine binding in phospholipase C enzymes.
Main Methods:
- Incorporation of fluorinated amino acids (pentafluorophenylalanine, difluorotyrosine) into proteins.
- Engineering of Staphylococcus aureus phosphatidylinositol-specific phospholipase C with a PC-binding site.
- Application to Bacillus thuringiensis phosphatidylinositol-specific phospholipase C.
Main Results:
- Fluorinated amino acids destabilize cation-π interactions via altered electrostatics.
- Increased hydrophobicity of fluorinated amino acids enhances membrane insertion.
- Successfully identified tyrosine residues involved in cation-π interactions in Bacillus thuringiensis phospholipase C.
Conclusions:
- Specific incorporation of fluorinated amino acids provides a facile method to differentiate cation-π interactions from membrane insertion.
- This methodology is applicable to various peripheral and integral membrane proteins.
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