ABSTRACT
In this chapter, past attempts and recent developments in mechanical extraction (or uprooting, the two term are used in this chapter with the same meaning) experiments of lipids, proteins, and nucleic acids mainly from biological entities but in some cases from arti¡cial surfaces using the atomic force microscope (AFM) have been considered. In the extraction process of phospholipids and proteins from cell membrane, their anchoring mechanism to the membrane must be broken. The biological membrane is made mainly of phospholipids and membrane proteins and has ±uid-like physical properties, thus being easily deformable under external stresses (Boal 2002). Anchoring of phospholipids and intrinsic membrane proteins to the lipid bilayer of such nature is secured mainly through hydrophobic interactions between non-polar segments of the membrane bound molecules and the hydrocarbon environment of the bilayer membrane (Tanford 1980). In the case of membrane proteins, the anchoring is sometimes augmented by the interactions between their intracellular domains and the cytoskeletal structure inside of the cell. We like to
8.1 Introduction ..................................................................................................209 8.2 Why Extract by Force? ................................................................................. 210 8.3 Preparation for Extraction Experiments ....................................................... 211 8.4 Extraction of Lipid Molecules ...................................................................... 213 8.5 Pulling Helical Polypeptides from the Lipid Bilayer Membrane ................. 216 8.6 Extraction of Intrinsic Membrane Proteins .................................................. 217 8.7 Proteins with Lipid Tethers ........................................................................... 223 8.8 Retrieval of Genomic DNA from Isolated Chromosomes ...........................224 8.9 Retrieval of Intracellular mRNA .................................................................. 227 8.10 Creating Membrane Holes Using AFM Probes ............................................228 8.11 Conclusions and Future Prospects ................................................................ 233 Acknowledgments ..................................................................................................234 References ..............................................................................................................234
know the mechanical strength of this anchoring system taking advantage of a recent development in nano-technological instruments, especially the AFM.
