RESUMO
The distribution of the electrostatic potential of T7 bacteriophage genome has been calculated. Promoter sites were localized in the electrostatic profile of T7-DNA. The electrostatic patterns of sigma70-specific promoters interacting with Escherichia coli RNA-polymerase were analyzed and compared with their functional behavior. Some specific electrostatic motifs were found in the upstream region of the promoters that may be involved in the differential recognition of promoter DNA by RNA-polymerase.
Assuntos
Bacteriófago T7/genética , DNA Viral/genética , RNA Polimerases Dirigidas por DNA/genética , Proteínas de Escherichia coli/genética , Genoma Viral , Regiões Promotoras Genéticas , Fator sigma/genética , Sequência de Bases , Dados de Sequência Molecular , Eletricidade EstáticaRESUMO
The oligonucleotide composition of the E. coli genome and its sigma70-specific promoters has been analyzed. The promoter DNA was shown to contain mainly AT-rich hexanucleotides having functionally important physical properties such as the ability to form easily melting sites and induce the bending of the double helix. A comparative analysis of the electrostatic characteristics of hexanucleotides within the whole sequence of the E. coli genome and its promoter regions was made. Hexanucleotides possessing a more electronegative surrounding were found to predominate in the nucleotide sequence of the promoter DNA.
Assuntos
Escherichia coli/genética , Escherichia coli/fisiologia , Genoma Bacteriano/genética , Potenciais da Membrana , Regiões Promotoras Genéticas/genética , Sequência de Bases/genética , RNA Polimerases Dirigidas por DNA/metabolismo , Análise de Sequência de DNA , Fator sigma/metabolismo , Eletricidade EstáticaRESUMO
Electrostatic profiles for sigma70-specific promoters of T4 bacteriophage and four consensus-like synthetic promoters have been calculated. It was shown that the promoters can be classified according to the presence of some specific electrostatic elements located in the far upstream region of their DNAs. A correlation between the electrostatic elements specific for promoters and their functional behaviour was established. A general scheme of promotor activity regulation through electrostatic interactions between the upstream region of promoter DNA and the RNA-polymerase a-subunit was suggested.
Assuntos
Bacteriófago T4/genética , RNA Polimerases Dirigidas por DNA/metabolismo , Regulação Viral da Expressão Gênica , Regiões Promotoras Genéticas , RNA Polimerases Dirigidas por DNA/química , Fator sigma/metabolismo , Eletricidade EstáticaRESUMO
The distribution of electrostatic potential of the complete sequence of the E. coli genome was calculated. It was found that DNA is not a uniformly charged molecule. There are some local inhomogeneities in its electrostatic profile, which correlate with the position of promoters in the genome. Electrostatic patterns of promoter DNAs can be specified due to the presence of some distinctive motifs, which may be involved as promoter signal elements in RNA-polymerase-promoter recognition.