High-molecular-weight DNA and the sedimentation coefficient: a new perspective based on DNA from T7 bacteriophage and two novel forms of T4 bacteriophage

Journal Article · Tue Jan 01 04:00:00 EST 1980 · J. Virol.; (United States)

OSTI ID:5344406

Clark, R W; Wever, G H; Wiberg, J S

The DNA molecules from T7 bacteriophage and a recently obtained mutant form of T4D were studied. The DNA of this T4 mutant contains cytosine in place of all of the glucosylated hydroxymethylcytosines normally present in T4. Molecular weights were measured with an electron microscope technique, and sedimentation coefficients were determined in isokinetic sucrose gradients. T7 DNA was found to have an M/sub r/ of 26.5 x 10/sup 6/. The T4 mutant, which we have termed T4c, produces two distinct phage head and DNA size classes. DNA from the standard heads (T4c DNA) has an M/sub r/ of 114.9 x 10/sup 6/, and DNA from the petite heads (T4cp DNA) has an M/sub r/ of 82.9 x 10/sup 6/. This enabled the derivation of an equation of sedimentation coefficient at zero concentration corrected to water at 20/sup 0/C versus M/sub r/ for the molecular weight range of 25 x 10/sup 6/ to 115 x 10/sup 6/ that is based solely on cytosine-containing DNA standards, thereby avoiding possible anomalies introduced by the glucosylation and hydroxymethylation of cytosine. The theory of Gray et al. provided the best description of the sedimentation coefficient versus M/sub r/ relationship, based on the sedimentation coefficients and the molecular weights of the three DNA standards and other evidence.

• Research Organization: Univ. of Rochester, NY
• OSTI ID: 5344406
• Journal Information: J. Virol.; (United States), Journal Name: J. Virol.; (United States) Vol. 33:1; ISSN JOVIA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
550700 -- Microbiology
59 BASIC BIOLOGICAL SCIENCES
AMINES
AZINES
BACTERIOPHAGES
CENTRIFUGATION
CYTOSINE
DNA
ELECTRON MICROSCOPY
HETEROCYCLIC COMPOUNDS
MICROORGANISMS
MICROSCOPY
MOLECULAR WEIGHT
MUTANTS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PARASITES
PYRIMIDINES
SEDIMENTATION
SEPARATION PROCESSES
STANDARDS
ULTRACENTRIFUGATION
VIRUSES