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ABCG5/G8 Crystallization in a Lipidic Bicelle Environment for X-Ray Crystallography
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Structure of ABC transporters.
Joseph K Zolnerciks1, Edward J Andress, Michael Nicolaou
1Blizard Institute of Cell and Molecular Science, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, The Blizard Building, 4 Newark Street, London E1 2AT, U.K.
Essays in Biochemistry
|October 5, 2011
Summary
ATP-binding cassette (ABC) transporters move molecules across membranes. This chapter reviews structural and biochemical evidence for ABC exporters, focusing on the controversial bellows-like mechanism for solute efflux.
Area of Science:
- Biochemistry
- Structural Biology
- Membrane Transport
Background:
- ABC transporters are active membrane proteins utilizing ATP hydrolysis for solute translocation.
- They comprise nucleotide-binding domains (NBDs) and transmembrane domains (TMDs).
- NBDs bind and hydrolyze ATP; TMDs form the translocation pathway and determine substrate specificity.
Purpose of the Study:
- To review structural, biochemical, and biophysical evidence concerning ABC exporters.
- To evaluate the proposed bellows-like mechanism for solute efflux mediated by ABC exporters.
Main Methods:
- Analysis of structural data from crystallized NBDs and intact ABC transporters.
- Biochemical and biophysical studies investigating transporter function and mechanism.
Main Results:
- Structural studies of isolated NBDs revealed nucleotide-binding and hydrolysis mechanisms.
- Structures of intact ABC importers and exporters provide insights into energy transduction.
- Evidence for and against the bellows-like efflux mechanism in ABC exporters is discussed.
Conclusions:
- Structural and functional studies have elucidated key aspects of ABC transporter mechanisms.
- The precise mechanism of solute efflux by ABC exporters, including the bellows-like model, remains an area of active investigation and debate.
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