Andreas Karner

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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(More)
Avidin and avidin-like proteins are widely used in numerous techniques since the avidin-biotin interaction is known to be very robust and reliable. Within this study, we investigated this bond at the molecular level under harsh conditions ranging from very low to very high pH values. We compared avidin with streptavidin and a recently developed avidin-based(More)
The von Willebrand factor (VWF) is a glycoprotein in the blood that plays a central role in hemostasis. Among other functions, VWF is responsible for platelet adhesion at sites of injury via its A1 domain. Its adjacent VWF domain A2 exposes a cleavage site under shear to degrade long VWF fibers in order to prevent thrombosis. Recently, it has been shown(More)
We here give information for a deeper understanding of single molecule force spectroscopy (SMFS) data through the example of the blood protein von Willebrand factor (VWF). It is also shown, how fitting of rupture forces versus loading rate profiles in the molecular dynamics (MD) loading-rate range can be used to demonstrate the qualitative agreement between(More)
Controversy regarding the number and function of ligand binding sites in neurotransmitter/sodium symporters arose from conflicting data in crystal structures and molecular pharmacology. Here, we have designed novel tools for atomic force microscopy that directly measure the interaction forces between the serotonin transporter (SERT) and the S- and(More)
The 2009 influenza pandemic originated from a swine-origin H1N1 virus, which, although less pathogenic than anticipated, may acquire additional virulence-associated mutations in the future. To estimate the potential risk, we sequentially passaged the isolate A/Hamburg/04/2009 in A549 human lung epithelial cells. After passage 6, we observed a 100-fold(More)
High-speed atomic force microscopy (HS-AFM) can be used to visualize function-related conformational changes of single soluble proteins. Similar studies of single membrane proteins are, however, hampered by a lack of suitable flat, non-interacting membrane supports and by high protein mobility. Here we show that streptavidin crystals grown on mica-supported(More)
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