Methylmercury-induced sedimentation heterogeneity of T7 bacteriophage DNA.

An endonuclease induced after infection of Escherichia coli with bacteriophage T7. I. Purification and properties of the enzyme.

A deoxyribonuclease has been purified 1,800-fold from Escherichia coli infected with bacteriophage T7. The enzyme has an approximate molecular weight of 18,000, requires a divalent cation for activity, and is inhibited by high concentrations of RNA. The purified enzyme catalyzes an endonucleolytic cleavage of both singleand double-stranded DNA. The rate of hydrolysis of single-stranded DNA is 1...

Variations in sedimentation patterns among deoxyribonucleic acids synthesized after infection of Escherichia coli by different amber mutants of bacteriophage T7.

Mutations induced by bacteriophage T7 RNA polymerase and their effects on the composition of the T7 genome.

We show here that transcription by the bacteriophage T7 RNA polymerase increases the deamination of cytosine bases in the non-transcribed strand to uracil, causing C to T mutations in that strand. Under optimal conditions, the mutation frequency increases about fivefold over background, and is similar to that seen with the Escherichia coli RNA polymerase. Further, we found that a mutant T7 RNA ...

Hexagonally packed DNA within bacteriophage T7 stabilized by curvature stress.

A continuum computation is proposed for the bending stress stabilizing DNA that is hexagonally packed within bacteriophage T7. Because the inner radius of the DNA spool is rather small, the stress of the curved DNA genome is strong enough to balance its electrostatic self-repulsion so as to form a stable hexagonal phase. The theory is in accord with the microscopically determined structure of b...

Gene 18 protein of bacteriophage T7. Overproduction, purification, and characterization.

Genetic and physical analyses indicate that gene 18 protein of bacteriophage T7 is essential for packaging of T7 DNA. T7 DNA is replicated via linear intermediates, culminating in the formation of concatemers many genomes in length which are then packaged into capsids. In infections with phage carrying amber mutations in gene 18, development is blocked at the concatemer stage. Biochemical studi...