Conformational Variability in Ground-State CFTR Lipoprotein Particle Cryo-EM Ensembles
Luba A Aleksandrov1, Adrei A Aleksandrov1, Timothy J Jensen1
1Biochemistry and Biophysics, University of North Carolina at Chapel Hill, 6107 Thurston Bowles Building, Chapel Hill, NC 27599, USA.
International Journal of Molecular Sciences
|August 26, 2022
Summary
Researchers visualized the cystic fibrosis transmembrane regulator (CFTR) ion channel using new methods. These techniques better mimic the CFTR protein's native membrane environment, aiding functional studies.
Area of Science:
- Structural biology
- Membrane protein biophysics
Background:
- Cystic fibrosis transmembrane regulator (CFTR) is an ion channel in the ABC transporter family.
- CFTR dysregulation leads to cystic fibrosis, impacting salt and water homeostasis.
- Previous CFTR structures were limited to detergent-purified preparations.
Purpose of the Study:
- To visualize CFTR in a more native-like membrane environment.
- To enable structural studies that better correlate with CFTR function.
- To overcome limitations of previous detergent-based purification methods.
Main Methods:
- Utilized two lipoprotein particle encapsulation techniques.
- Reconstitution of purified CFTR using Saposin A.
- Direct extraction of CFTR from membranes using Sokalan CP9 (DIBMA).
Main Results:
- Obtained structures of CFTR in lipid environments using novel methods.
- These preparations offer a closer representation of CFTR's native state.
- Enables functional studies, such as single-channel measurements in membrane vesicles.
Conclusions:
- Novel encapsulation techniques provide better models for CFTR structural and functional studies.
- These methods advance our understanding of CFTR in a near-native state.
- Facilitates research into cystic fibrosis mechanisms and potential therapeutics.
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