The Analysis Of Chemical Features In The Core Promoter Of Escherichia Coli

Transcription is the first major step in gene expression, and constitutes an important point of genetic information flow. Promoter determines the position of transcriptional start point and the frequency with which the gene is transcribed, so promoter analysis is important for genome annotation. Gene composition and structure of the prokaryotic pattern organism are simple relative to the human gene. During the period of genome sequencing not only it provided reference for Human Genome Project, but also to understand function gene of these prokaryotic pattern organism provided more help for clearly recognizing function of human genome and impels genome research methods and technology development.In the field of DNA numerical value mapping, simple, artificial evaluation for A, T, C, and G cannot reflect the biology significance of DNA sequence completely. Base on this, we proposed physical and chemical properties of nucleic acid were used to mapping DNA sequences. Compared with the existing method it can reflect more biology information, and is more suitable to apply in analyzing the DNA sequence in signal processing methods.As one of prokaryotic pattern organism, the promoter of E. coli was the object of this study. Its sequence data was from the NCBI database. When the core promoter sequence of Escherichia coli (E. coli) was translated into digital signals with chemical properties of nucleic acid, wavelet analysis was employed to find out the chemical features of the core promoter sequence. The results of this investigation confirmed the vital role of characteristic modules -10 region and -35 region in regulation, and their possible reaction pathways and positions were discussed. That is to say, the 0 atom in the nucleotide T formed the hydrogen bond with RNA polymerase as the hydrogen acceptor to become the function site of-35 region; The possibility was lower for -10 region to become hydrogen donors and hydrogen acceptors. It is possible the Van der Waals function was the main action fashion with RNAP. The structural orientation might be a key factor for RNA polymerase combined with DNA and P atoms would become the target site of action in this configuration. Furthermore, a novel feature was discovered firstly at -53 region. Not only -53 region rich in A, but also we could confer that a specific structure of RNA polymerase interacted with DNA by means of non-hydrogen bond. It could be initial site where the DNA sequence was combined with the RNA polymerase.Promoter recognition is one of important questions in bioinformatics. The descriptors of chemical feature obtained in this study provided the reference value for exploring promoter recognition and forecast.The structure of full text as follows:Chapter 1 was an introduction. It has simply introduced bioinformation related knowledge, some databases in bioinformation, as well as the current situation and method of promoter research.Chapter 2------Studying of a new method in sequence analysis. First, introduced theimportant effect of chemical structures for DNA sequence behavior. Next, we analyzed and compared various numerical mapping methods, then introduced new one. Finally, Introduced relevance knowledge of wavelet analysis used in this paper and analyzed and discussed the selection of wavelet functions.Chapter 3 has separately discussed subunits and function of RNA polymerase, as well as prokaryotic promoter elements and the recognition of characteristic elements.Chapter 4------The analysis of chemical features in core promoter of E. coli.