期刊名称:Proceedings of the National Academy of Sciences
印刷版ISSN:0027-8424
电子版ISSN:1091-6490
出版年度:1981
卷号:78
期号:7
页码:4274-4278
DOI:10.1073/pnas.78.7.4274
语种:English
出版社:The National Academy of Sciences of the United States of America
摘要:We have determined the sequences of the ssb gene and protein of Escherichia coli. The coding region of ssb is 534 base pairs and is preceeded and followed by dyad symmetries of 39 base pairs and 27 base pairs, respectively. The promoter for ssb is close to that for uvrA and these two genes are transcribed in opposite directions: ssb clockwise and uvrA counterclockwise on the standard E. coli genetic map. The DNA helix-destabilizing protein encoded by the ssb gene (single-strand binding protein) contains 177 amino acids and has a calculated molecular weight of 18,873. Although there is no extensive sequence homology among the three helix-destabilizing proteins whose sequences are now known, both the E. coli and bacteriophage T4 DNA helix-destabilizing proteins do contain an acidic, alpha-helical region at their carboxy termini that may be functionally homologous. The remainder of the E. coli helix-destabilizing protein can be divided into two apparent domains on the basis of its amino acid sequence. The amino-terminal region (residues 1-105) contains 79% of the charged residues (27 out of 34 total) in the protein and is predicted to have a high degree of secondary structure (alpha helix and beta pleated sheet). In contrast, the region including residues 106-165 contains only two charged amino acids and is devoid of alpha helix or beta pleated sheet.