Virus maturation involving large subunit rotations and local refolding.
Large-scale conformational changes transform viral precursors into infectious virions. The structure of bacteriophage HK97 capsid, Head-II, was recently solved by crystallography, revealing a catenated cross-linked topology. We have visualized its precursor, Prohead-II, by cryoelectron microscopy and modeled the conformational change by appropriately adapting Head-II. Rigid-body rotations ( approximately 40 degrees) cause switching to an entirely different set of interactions; in addition, two motifs undergo refolding. These changes stabilize the capsid by increasing the surface area buried at interfaces and bringing the cross-link-forming residues, initially approximately 40 angstroms apart, close together. The inner surface of Prohead-II is negatively charged, suggesting that the transition is triggered electrostatically by DNA packaging.
Conway
J F
JF
Laboratory of Structural Biology Research, National Institute of Arthritis, Musculoskeletal and Skin Diseases, Bethesda, MD 20892, USA.
Wikoff
W R
WR
Cheng
N
N
Duda
R L
RL
Hendrix
R W
RW
Johnson
J E
JE
Steven
A C
AC
D020816:Amino Acid Motifs; D002213:Capsid / Q000737:chemistry* / Q000378:metabolism*; D020285:Cryoelectron Microscopy; D018360:Crystallography, X-Ray; D004279:DNA, Viral / Q000378:metabolism; D007091:Image Processing, Computer-Assisted; D008958:Models, Molecular; D011487:Protein Conformation; D017510:Protein Folding; D011498:Protein Precursors / Q000737:chemistry* / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D017906:Siphoviridae / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D013499:Surface Properties; D019065:Virus Assembly
D004279:DNA, Viral; D011498:Protein Precursors; D021122:Protein Subunits