Three-dimensional architecture of the bacteriophage phi29 packaged genome and elucidation of its packaging process.
The goal of the work reported here is to understand the precise molecular mechanism of the process of DNA packaging in dsDNA bacteriophages. Cryo-EM was used to directly visualize the architecture of the DNA inside the capsid and thus to measure fundamental physical parameters such as inter-strand distances, local curvatures, and the degree of order. We obtained cryo-EM images of bacteriophage that had packaged defined fragments of the genome as well as particles that had partially completed the packaging process. The resulting comparison of structures observed at intermediate and final stages shows that there is no unique, deterministic DNA packaging pathway. Monte Carlo simulations of the packaging process provide insights on the forces involved and the resultant structures.
Comolli
Luis R
LR
Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Spakowitz
Andrew J
AJ
Siegerist
Cristina E
CE
Jardine
Paul J
PJ
Grimes
Shelley
S
Anderson
Dwight L
DL
Bustamante
Carlos
C
Downing
Kenneth H
KH
D017103:Bacillus Phages / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure*; D020285:Cryoelectron Microscopy; D042003:DNA Packaging; D004279:DNA, Viral / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure*; D016679:Genome, Viral; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008958:Models, Molecular; D009010:Monte Carlo Method; D009690:Nucleic Acid Conformation; D014771:Virion / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure
D004279:DNA, Viral