Measurements of DNA lengths remaining in a viral capsid after osmotically suppressed partial ejection

Submitted by Ajaykumar Gopal on Sun, 07/06/2008 - 21:41.
Tags:

Publication Type:

Journal Article

Authors:

Evilevitch, A.; Gober, J.; Phillips, M.; Knobler, C.; Gelbart, W.

Source:

BIOPHYSICAL JOURNAL, Volume 88, Number 1, p.751-756 (2005)

URL:

http://dx.doi.org/10.1529/biophysj.104.045088

Keywords:

BACTERIOPHAGE-LAMBDA; SEDIMENTATION; EXPRESSION; FORCES; PHAGE

Abstract:

The effect of external osmotic pressure on the extent of DNA ejection from bacteriophage-lambda was recently investigated (Evilevitch et al., 2003). The total length of DNA ejected was measured via the 260-nm absorption by free nucleotides, after opening of the capsids in the presence of varying amounts of polyethylene glycol 8000 and DNase I. As a function of osmolyte concentration, this absorption was shown to decrease progressively, ultimately vanishing completely for a sufficiently high external osmotic pressure. In this work we report the results of both sedimentation and gel analysis of the length of DNA remaining inside the capsids, as a function of osmolyte concentration. It is confirmed in this way that the progressive inhibition of DNA ejection corresponds to partial ejection from all of the capsids.