The conformation and dynamics of P-glycoprotein in a lipid bilayer investigated by atomic force microscopy
| Autor: | Laura A. Wilt, Krishna P. Sigdel, Arthur G. Roberts, Gavin M. King, Brendan P. Marsh |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Pharmacology integumentary system Protein Conformation Chemistry Lipid Bilayers Context (language use) Transporter Crystal structure Microscopy Atomic Force Biochemistry Article Mice 03 medical and health sciences 030104 developmental biology Membrane Protein structure ATP hydrolysis Liposomes Biophysics Animals Molecule ATP Binding Cassette Transporter Subfamily B Member 1 Lipid bilayer |
| Zdroj: | Biochemical Pharmacology. 156:302-311 |
| ISSN: | 0006-2952 |
| Popis: | The membrane-bound P-glycoprotein (Pgp) transporter plays a major role in human disease and drug disposition because of its ability to efflux a chemically diverse range of drugs through ATP hydrolysis and ligand-induced conformational changes. Deciphering these structural changes is key to understanding the molecular basis of transport and to developing molecules that can modulate efflux. Here, atomic force microscopy (AFM) is used to directly image individual Pgp transporter molecules in a lipid bilayer under physiological pH and ambient temperature. Analysis of the Pgp AFM images revealed “small” and “large” protrusions from the lipid bilayer with significant differences in protrusion height and volume. The geometry of these “small” and “large” protrusions correlated to the predicted extracellular (EC) and cytosolic (C) domains of the Pgp X-ray crystal structure, respectively. To assign these protrusions, simulated AFM images were produced from the Pgp X-ray crystal structures with membrane planes defined by three computational approaches, and a simulated 80 A AFM cantilever tip. The theoretical AFM images of the EC and C domains had similar heights and volumes to the “small” and “large” protrusions in the experimental AFM images, respectively. The assignment of the protrusions in the AFM images to the EC and C domains was confirmed by changes in protrusion volume by Pgp-specific antibodies. The Pgp domains showed a considerable degree of conformational dynamics in time resolved AFM images. With this information, a model of Pgp conformational dynamics in a lipid bilayer is proposed within the context of the known Pgp X-ray crystal structures. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect