Research On Fractal Structures And Functions Of Proteins

As essential material of constituting the organism, the protein has played important biological functions that are largely dependent on its structure. To know completely the biological function of the protein, further research on the protein structure is highly required. At present, the mechanism on how the peptide chain is folded into the protein structure is not yet known clearly. However among protein structure prediction, the prediction of protein secondary structure has become very necessary, for it connects amino acid sequences with tertiary structure of protein. The prediction of secondary structure is the base of setting up a model of tertiary structure of protein. In the past twenty years, although scientists have made great efforts to solve this problem, satisficatory results have not yet been achieved. Nowadays, only the accuracy of 76% can be got by available methods, which is far away from requirements.In this thesis, three investigations have been done: Firstly, the relation between fractal dimension and protein structure is considered basing on maximal-flux principle foundation. The mechanism on how the peptide chain is folded in the spatial protein structure is revealed by the mathematical formalisms, which may provide important implications for the study the biological function of the protein and the analysis of life origin. The different fractal dimensions manifest the different topology structures, and the fractal dimension is influenced by the environmental factor a. Therefore, the environmental factor a may be taken as a standard of recognizing protein structure. Secondly, because the similarity exists among the protein structures, the self-organizing map (SOM), whose similarity is strongest among genetic neural network algorithm, is chosen to predict protein secondary structure. Three percentage points precision enhancement of predictive results on protein secondary structure prediction is obtained, which will speed the protein structure prediction. Thirdly, the protein spatial structure decides its biology function, however the protein spatial structure is restricted by the fractal dimension and the environmental factor a. Therefore, the prediction of the protein biological function is elaborated by the biological evolution viewpoint, from two aspects as fractal dimension and environmental factor, which may promote the understanding on the mechanism of the protein molecular disease and the medicine molecule design as well, and may finally improve the research on the protein biological function of the towards the human demands.