Sedimentation Coefficient and Fragility under Hydrodynamic Shear as Measures of Molecular Weight of the DNA of Phage T5

Abstract

T5 DNA molecules resemble fragments of T2 DNA of molecular weight 84 x 10(6) with respect to sedimentation coefficient and susceptibility to breakage under hydrodynamic shear. The sedimentation coefficient falls by the same factor when either T2 or T5 DNA is broken at its characteristic critical shear rate. At a given high rate of shear, both DNA's are broken into fragments exhibiting the same sedimentation coefficient. It follows that 84 x 10(6) is a proper estimate of the molecular weight of T5 DNA, and that particles of phage T5, like those of T2, contain a single DNA molecule.