Experimental Test of Connector Rotation during DNA Packaging into Bacteriophage [phi]29 Capsids: e59

The bacteriophage φ29 generates large forces to compact its double-stranded DNA genome into a protein capsid by means of a portal motor complex. Several mechanical models for the generation of these high forces by the motor complex predict coupling of DNA translocation to rotation of the head-tail c...

Full description

Saved in:
Bibliographic Details
Published in:PLoS biology 2007-03, Vol.5 (3)
Main Authors: Hugel, Thorsten, Michaelis, Jens, Hetherington, Craig L, Jardine, Paul J, Grimes, Shelley, Walter, Jessica M, Falk, Wayne, Anderson, Dwight L, Bustamante, Carlos
Format: Article
Language:English
Subjects:
Biophysics
Cameras
Experiments
Genomes
Hypotheses
Microscopy
Packaging machinery
RNA polymerase
Spectrum analysis
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The bacteriophage φ29 generates large forces to compact its double-stranded DNA genome into a protein capsid by means of a portal motor complex. Several mechanical models for the generation of these high forces by the motor complex predict coupling of DNA translocation to rotation of the head-tail connector dodecamer. Putative connector rotation is investigated here by combining the methods of single-molecule force spectroscopy with polarization-sensitive single-molecule fluorescence. In our experiment, we observe motor function in several packaging complexes in parallel using video microscopy of bead position in a magnetic trap. At the same time, we follow the orientation of single fluorophores attached to the portal motor connector. From our data, we can exclude connector rotation with greater than 99% probability and therefore answer a long-standing mechanistic question.
ISSN:1544-9173
1545-7885
DOI:10.1371/journal.pbio.0050059