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High-speed atomic force microscopy shows that annexin V stabilizes membranes on the second timescale. Annexins are abundant cytoplasmic proteins that can bind to negatively charged phospholipids in a Ca2+-dependent manner, and are known to play a role in the storage of Ca2+ and membrane healing. Little is known, however, about the dynamic processes of protein– Ca2+–membrane assembly and disassembly. Here we show that high-speed atomic force microscopy (HS-AFM) can be used to repeatedly induce and disrupt annexin assemblies and study their structure, dynamics and interactions. Our HS-AFM set-up is adapted for such biological applications through the integration of a pumping system for buffer exchange and a pulsed laser system for uncaging caged compounds. We find that biochemically identical annexins (annexin V) display different effective Ca2+ and membrane affinities depending on the assembly location, providing a wide Ca2+ buffering regime while maintaining membrane stabilization. We also show that annexin is membrane-recruited and forms stable supramolecular assemblies within ∼5 s in conditions that are comparable to a membrane lesion in a cell. Molecular dynamics simulations provide atomic detail of the role played by Ca2+ in the reversible binding of annexin to the membrane surface. Nature Nanotechnology, 2016.

Recent publications

Bignon, E.; Gattuso, H.; Morell, C.; Dehez, F.; Georgakilas, A. G.; Monari, A. & Dumont, E.
Correlation of bistranded clustered abasic DNA lesion processing with structural and dynamic DNA helix distortion.
Nucleic Acids Res.

2016,  (44), 8588-8599.
dx.doi.org

Wang, S.; Zhao, T.; Shao, X.; Chipot, C.; Cai, W.
Complex movements in rotaxanes: Shuttling coupled with conformational transition of cyclodextrins
J. Phys. Chem. C

2016,  (120), 19479-19486.
dx.doi.org

Gattuso, H.; Durand, E.; Bignon, E.; Morell, C.; Georgakilas, A. G.; Dumont, E.; Chipot, C.; Dehez, F.; Monari, A.
Repair rate of clustered abasic DNA lesions by human endonuclease: Molecular bases of sequence specificity
J. Phys. Chem. Lett

2016,  (19), 3760-3765.
dx.doi.org

News

- Renewal of the Laboratoire International Associé CNRS-University of Illinois at Urbana-Champaign on November 2016
- An update of ParseFEP is available in the latest version of VMD.
- 新的分子动力学讲义 (Dissemination).
 

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