The Study Of Biological Macromolecules With Atomic Force Microscopy

Our knowledge on three-dimension structures and states of biomolecules is the important foundation for further understanding molecular functions and life phenomena. Atomic force microscope (AFM) detection advantages include high resolution and visualization. The samples'preparation is very simple. There is no complex samples'disposal processes required, such as dehydration,vacuumizing,dyeing and embedment. These processes are likely to change the biomolecular structures. AFM is also able to detect the biomolecular dynamic structure information in near living condition. Because of these characters, AFM become an powerful analytical and detecting tool for structures and functions of biomolecules. So, AFM have been applied rapidly in biology since they were produced.The states and accumulation process of cytochrome C were studied by AFM. the interaction between the organic probe (chrome azurol S,Bromophenol blue)– cetyltrime thylammonium bromide and DNA were researched, and the mechanism of DNA determination with resonance light scattering(RLS) was discussed. Our research work involved the following contents and achievements:1. The states of cytochrome C molecules in different concentration and the states changed by addition of urea were studied with AFM. It was found that the cytochrome C molecules in low concentration are mainly spheroid monomer states. The cytochrome C would aggregate under given higher concentration. And within a certain range of concentration, the cytochrome C molecules were inclined to form the bigger aggregations as the concentration increased. The aggregation of cytochrome C molecules was reduced by high concentration urea. The three-dimension of monomers and aggregations had also been measured and analyzed.2. The accumulation process of cytochrome C in warm water and the influence of some exterior factors were studied by AFM. The cytochrome C accumulation states in different moments were observed. The results showed that the cytochrome C molecules had strong interaction each other. They were able to assemble and form the regular helix fibre accumulation in water. The environmental factors had obvious influence on accumulation process. Salt ion could produce synergistic effects on accumulation of cytochrome C. The accumulating model and mechanism of cytochrome C were discussed.