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SUMMARY:Atomic force microscopy and force spectroscopy of membrane protein
 s - Joint seminar with Nanoscience - Sonja Contera\, Dept. of Physics\, Un
 iversity of Oxford
DTSTART:20051125T153000Z
DTEND:20051125T163000Z
UID:TALK4331@talks.cam.ac.uk
CONTACT:Duncan Simpson
DESCRIPTION:Membrane proteins are compact\, highly versatile proteins that
  work inserted in the lipid bilayers that separate the cell from its surro
 undings. They can act as transporters and pores\, motors\, switches and pu
 mps of ions. They can sense touch\, temperature\, light and volume\, and t
 ransduce energy. The large variety of functions of membrane proteins promi
 ses an equally large number of possible applications and devices. Membrane
  proteins constitute about 30% of all the proteins encoded in the human ge
 nome\, and represent the most important class of drug targets: about 50%. 
 However\, only about 2% of the 3D structures in the Protein Data Bank are 
 membrane proteins. The number of high-resolution structures is even smalle
 r\, mainly because of the difficulties in crystallising them. \nA main obj
 ective of atomic force microscopy (AFM) studies of proteins is to directly
  observe with high resolution their functional behaviour\, particularly th
 eir conformational changes in response to drugs etc. in real time. \nWe us
 e AFM\, Dynamic Force Spectroscopy (DFS) and High-Speed AFM* to study the 
 structure and the mechanisms that membrane proteins use for functioning in
 serted in lipid bilayers. In particular\, we have studied by DFS the role 
 of tryptophan residues in membrane protein anchoring using synthetic WALP 
 peptides. Experimental results are complemented by Molecular Dynamics simu
 lations. \nWe have used AFM and DFS to study the mechanical properties of 
 Purple Membranes. The effect of salt and pH on the interaction between lip
 ids and proteins\, the electrostatics and the membrane cohesion were also 
 investigated. \nI will show our work towards improving the resolution and 
 sensitivity of AFM and High-Speed AFM in solution by studying short-range 
 forces at the membrane-double layer region. Our high resolution studies re
 veal local variations of the force fields near the membrane surface\, name
 ly ions affecting locally protein-lipid interactions. \nFinally\, I will p
 resent our studies on interfacing membranes and membrane proteins with nan
 o-structures aiming at the fabrication of bioelectronic devices using carb
 on nanotubes\, n-doped carbon nanotubes and nano-gap electrodes. \n
LOCATION:IRC in Superconductivity Seminar Room\, Cavendish Laboratory
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