New Approach for Atomic Force Microscopy of Membrane Proteins: The Imaging of Cholera Toxin

• Published in: Journal of molecular biology Vol. 229; no. 2; pp. 286 - 290
• Main Authors: Yang, Jie, Tamm, Lukas K., Tillack, Thomas W., Shao, Zhifeng
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 20.01.1993; Elsevier
• Subjects: Analytical, structural and metabolic biochemistry; atomic force microscopy; Biological and medical sciences; cholera toxin; Cholera Toxin - chemistry; Fundamental and applied biological sciences. Psychology; General aspects, investigation methods; Langmuir-Blodgett films; Lipid Bilayers; membrane protein structure; Membrane Proteins - ultrastructure; Microscopy - methods; Proteins; supported lipid bilayers; supported lipid bilayers; Langmuir-Blodgett films; cholera toxin; atomic force microscopy; membrane protein structure; Infection; Atomic force microscopy; Toxin; Membrane protein; Investigation method; Bacteriosis; Cholera; Artificial membrane; Structural analysis
• ISSN: 0022-2836; 1089-8638
• DOI: 10.1006/jmbi.1993.1033

We demonstrate that supported synthetic phospholipid bilayers, which are stabilized by lateral cross-linking in both leaflets, can be used for specimen preparation for atomic force microscopy of purified membrane proteins with high stability and excellent reproducibility under water or low-salt buffer. A bilayer containing 1,2-dipentacosa-10,12-diynoyl-phosphatidylcholine and 20 mol% ganglioside (GMI) was transferred onto the surface of mica from a Langmuir trough. Cholera toxin, both the B-subunit and the complete molecule randomly bound to the gangliosides, were imaged by atomic force microscopy in solution with a resolution of better than 2 nm. The pentameric structure of the B-subunit oligomers was well resolved. This result indicates that, with this preparation procedure, other membrane proteins may be studied at intermediate to high resolution under physiologically relevant conditions without the need for crystallization.