title: Force-induced conformational change of bacteriorhodopsin.
abstract: The cytoplasmic surface topography of purple membranes imaged by the atomic force microscope depends mainly on the force applied to the stylus. Imaged at forces of 300 pN, individual bacteriorhodopsin molecules reveal two domains. The resulting donut-shaped trimers reversibly transform into structures exhibiting three prominent protrusions when scanned at 100 pN. In parallel, the height of the protein moiety above the lipid layer increases from 4 A to 6 A. From the known structure of bacteriorhodopsin it appears that this change may be related to a bending of the most prominent cytoplasmic loop.
authors.affiliation: M. E. Müller-Institute for Structural Biology Biozentrum, University of Basel, Switzerland.
authors.forename: D J
authors.initials: DJ
authors.lastname: Müller
authors.forename: G
authors.initials: G
authors.lastname: Büldt
authors.forename: A
authors.initials: A
authors.lastname: Engel
mesh_terms: D001436:Bacteriorhodopsins / Q000737:chemistry* / Q000648:ultrastructure; D006863:Hydrogen-Ion Concentration; D018625:Microscopy, Atomic Force / Q000379:methods; D011487:Protein Conformation; D013314:Stress, Mechanical
chemical_list: D001436:Bacteriorhodopsins