Scanning probe microscopy of proteins and protein-membrane complexes

The main advances in the investigation of proteins and protein-membrane com plexes achieved in recent years using the scanning tunneling microscopy and atomic force microscopy (STM and AFM, respectively) techniques are reviewe d. The operational principles of STM and AFM in different regimes are descr ibed briefly. The potentialities for studying isolated proteins, proteins o f cytoplasmic and cell membranes, and protein crystals are discussed in det ail. The importance of direct measurement of the forces of intermolecular i nteraction and the application of this approach to immunology are emphasize d. The advantages of the STM and AFM methods in studying proteins and their complexes in situ are demonstrated. The specific features of the visualiza tion of biological objects hampering their study by scanning probe microsco py are noted. New problems and prospects in the development of probe micros copy are discussed.