The Research Of Graphical Representation Of Protein Sequences And Its Application

As the foundation of lives, proteins possess extreme important role in the research of bioscience. The research for proteins is mainly focusing on the revealing of their structures, functions and so on. It’s generally accepted that the structure of the molecular determines its function. And for a given protein, its primary structure determines its spatial structure. Thus, the study of the primary structures is the foundation of the research for proteins.The comparison of proteins is one of the main ways to analyze them. However the traditional methods that based on the sequence alignments have some disadvantages such as the high complexity for comparing and storing, the lack of visuality and so on. That’s why some non-alignment methods for sequence comparison have been proposed. Graphical representation is one of the non-alignment methods for overcoming these problems during the analysis of biological sequences, which has been studied widely.This thesis is mainly focusing on the study of the graphical representation methods for analyzing protein sequences and their applications. The innovation of this thesis can be concluded as follows:First of all, three kinds of graphical representation methods have been proposed for the visual analysis of protein sequences. These three methods are based on the characteristic model of protein sequences, the recurrence plot and the ADLD graphs respectively. The graphs are 2-D graphs which can be analyzed with good visuality. Among them, the characteristic model of protein sequences based method is very simple. The corresponding graphs are composed of fix number of plots. The recurrence plot is a kind of mature nonlinear analysis technology, so that the recurrence plot based method possess good theoretical basis. And the ADLD graph based method can be used to analysis the inner differences of a protein pairs and the results are more accurate.Then, the applications of those proposed graphical representation methods have been discussed. The applications in this thesis mainly include the similarity analysis of protein sequences and the construction of the phylogenetic tree of different species. By computing the distance between the curves or the characteristics of the curves for those protein sequences, we can analyze the similarity/dissimilarity between those sequences. On the other hand, one can construct the phylogenetic tree of the species based on the distance matrix of them and some existing algorithms.Finally, the thesis has discussed some of the other kinds of applications of the graphical representation methods. And, some of the expectations of the application of this kind of technology have been provided. The good visuality, numerical of the similarity/ dissimilarity and the low complexity and so on allow the widely usage of this kind of techniques in the future.