The primosomal protein n' of Escherichia coli is a DNA helicase.
Protein n' of Escherichia coli functions in assembly and translocation of the primosome, a mobile multiprotein complex involved in priming DNA replication (Kornberg, A. (1982) Supplement to DNA Replication, Freeman Publications, San Francisco). By itself, protein n' translocates on single-stranded DNA and destabilizes duplex regions by acting as a DNA helicase, using the energy of ATP or dATP hydrolysis. Single-stranded DNA binding protein was required for melting of duplex regions longer than 40 base pairs. Initial binding of protein n' to a specific site on DNA (Shlomai, J., and Kornberg, A. (1980) Proc. Natl. Acad. Sci. U.S.A. 77, 799-803) is essential for its helicase function. The polarity of protein n' translocation on DNA, in the 3' to 5' direction of the chain, suggests a mechanism for how the primosome may contribute to concurrent replication of both strands at a replication fork.
Lasken
R S
RS
Department of Biochemistry, Stanford University School of Medicine, California 94305.
Kornberg
A
A
D000255:Adenosine Triphosphate / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism*; D001435:Bacteriophages; D004265:DNA Helicases / Q000378:metabolism*; D004261:DNA Replication; D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000378:metabolism; D004279:DNA, Viral / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000201:enzymology*; D013379:Substrate Specificity
D001426:Bacterial Proteins; D004277:DNA, Single-Stranded; D004279:DNA, Viral; D000255:Adenosine Triphosphate; D004265:DNA Helicases; D004264:DNA Topoisomerases, Type I