A Caltech Library Service

Ion-Dependent Dynamics of DNA Ejections for Bacteriophage λ

Wu, David and Van Valen, David and Hu, Qicong and Phillips, Rob (2010) Ion-Dependent Dynamics of DNA Ejections for Bacteriophage λ. Biophysical Journal, 99 (4). pp. 1101-1109. ISSN 0006-3495. PMCID PMC2920739.

PDF (Document S1. Figures. ) - Supplemental Material
See Usage Policy.

[img] Video (AVI) (Movie S1: An optically trapped looped ejection) - Supplemental Material
See Usage Policy.


Use this Persistent URL to link to this item:


We studied the control parameters that govern the dynamics of in vitro DNA ejection in bacteriophage λ. Previous work demonstrated that bacteriophage DNA is highly pressurized, and this pressure has been hypothesized to help drive DNA ejection. Ions influence this process by screening charges on DNA; however, a systematic variation of salt concentrations to explore these effects has not been undertaken. To study the nature of the forces driving DNA ejection, we performed in vitro measurements of DNA ejection in bulk and at the single-phage level. We present measurements on the dynamics of ejection and on the self-repulsion force driving ejection. We examine the role of ion concentration and identity in both measurements, and show that the charge of counterions is an important control parameter. These measurements show that the mobility of ejecting DNA is independent of ionic concentrations for a given amount of DNA in the capsid. We also present evidence that phage DNA forms loops during ejection, and confirm that this effect occurs using optical tweezers.

Item Type:Article
Related URLs:
URLURL TypeDescription DOIArticle CentralArticle information - PDF file information - AVI file
Van Valen, David0000-0001-7534-7621
Phillips, Rob0000-0003-3082-2809
Additional Information:© 2010 Biophysical Society. Published by Elsevier. Received 1 March 2010; accepted 9 June 2010. Editor: Laura Finzi.. Available online 17 August 2010. The authors thank the members of the physiology course at the Marine Biology Laboratory in Woods Hole, MA (Nicolas Chiaruttini, Paul Grayson, Zenan Chang, Alexander Grosberg, Ian Molineux, Michael Rubinstein, Virgile Viasnoff, William Gelbart, and Charles Knobler), and members of the Phillips laboratory. D.W. and D.V.V. were supported by a National Institutes of Health (NIH) Medical Scientist Training Program Fellowship. D.V.V. was supported by a Yaser Abu-Mostafa Hertz Fellowship and an NIH Director’s Pioneer Award. R.P., D.W., and D.V.V. were supported by National Science Foundation grant No. 0758343 and an NIH Pioneer Award. Q.H. was supported by a predoctoral fellowship (BC083077) from the Department of Defense Breast Cancer Research Program.
Funding AgencyGrant Number
Yaser Abu-Mostafa Hertz FellowshipUNSPECIFIED
Department of Defense Breast Cancer Research ProgramBC083077
Issue or Number:4
PubMed Central ID:PMC2920739
Record Number:CaltechAUTHORS:20100907-101147251
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:19796
Deposited By: Tony Diaz
Deposited On:08 Sep 2010 17:08
Last Modified:03 Oct 2019 02:01

Repository Staff Only: item control page