title: High-speed AFM images of thermal motion provide stiffness map of interfacial membrane protein moieties.
abstract: The flexibilities of extracellular loops determine ligand binding and activation of membrane receptors. Arising from fluctuations in inter- and intraproteinaceous interactions, flexibility manifests in thermal motion. Here we demonstrate that quantitative flexibility values can be extracted from directly imaging the thermal motion of membrane protein moieties using high-speed atomic force microscopy (HS-AFM). Stiffness maps of the main periplasmic loops of single reconstituted water channels (AqpZ, GlpF) revealed the spatial and temporal organization of loop-stabilizing intraproteinaceous H-bonds and salt bridges.
authors.affiliation: Center for Advanced Bioanalysis GmbH , Gruberstrasse 40, 4020 Linz, Austria.
authors.forename: Johannes
authors.initials: J
authors.lastname: Preiner
authors.forename: Andreas
authors.initials: A
authors.lastname: Horner
authors.forename: Andreas
authors.initials: A
authors.lastname: Karner
authors.forename: Nicole
authors.initials: N
authors.lastname: Ollinger
authors.forename: Christine
authors.initials: C
authors.lastname: Siligan
authors.forename: Peter
authors.initials: P
authors.lastname: Pohl
authors.forename: Peter
authors.initials: P
authors.lastname: Hinterdorfer
mesh_terms: D020346:Aquaporins / Q000737:chemistry*; D004926:Escherichia coli / Q000737:chemistry*; D029968:Escherichia coli Proteins / Q000737:chemistry*; D018625:Microscopy, Atomic Force / Q000379:methods*; D017433:Protein Structure, Secondary
chemical_list: D020346:Aquaporins; D029968:Escherichia coli Proteins; C106425:aqpZ protein, E coli; C078043:GlpF protein, E coli
keywords: AqpZ; GlpF; Single molecule; flexibility; high speed atomic force microscopy; membrane proteins