The structure of an infectious P22 virion shows the signal for headful DNA packaging.
Bacteriophages, herpesviruses, and other large double-stranded DNA (dsDNA) viruses contain molecular machines that pump DNA into preassembled procapsids, generating internal capsid pressures exceeding, by 10-fold, that of bottled champagne. A 17 angstrom resolution asymmetric reconstruction of the infectious P22 virion reveals that tightly spooled DNA about the portal dodecamer forces a conformation that is significantly different from that observed in isolated portals assembled from ectopically expressed protein. We propose that the tight dsDNA spooling activates the switch that signals the headful chromosome packing density to the particle exterior.
Lander
Gabriel C
GC
Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
Tang
Liang
L
Casjens
Sherwood R
SR
Gilcrease
Eddie B
EB
Prevelige
Peter
P
Poliakov
Anton
A
Potter
Clinton S
CS
Carragher
Bridget
B
Johnson
John E
JE
D017100:Bacteriophage P22 / Q000235:genetics* / Q000502:physiology / Q000648:ultrastructure*; D002213:Capsid / Q000737:chemistry / Q000648:ultrastructure*; D036022:Capsid Proteins / Q000737:chemistry; D020285:Cryoelectron Microscopy; D018360:Crystallography, X-Ray; D042003:DNA Packaging; D004279:DNA, Viral / Q000032:analysis* / Q000737:chemistry; D007091:Image Processing, Computer-Assisted; D009690:Nucleic Acid Conformation; D011312:Pressure; D011487:Protein Conformation; D014771:Virion / Q000235:genetics / Q000648:ultrastructure*
D036022:Capsid Proteins; D004279:DNA, Viral