Virus Maturation Involving Large Subunit Rotations and Local Refolding

• DOI: 10.1126/science.1058069
• Publication Date: 2002-07-27T09:52:41Z
• Authors: J. F. Conway; W. R. Wikoff; N. Cheng; R. L. Duda; R. W. Hendrix; J. E. Johnson; A. C. Steven
• Keywords: Conformational change; Angstrom

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, cryoelectron microscopy and modeled the change appropriately adapting Head-II. Rigid-body rotations (∼40 degrees) cause switching to an entirely different set interactions; in addition, two motifs undergo refolding. These stabilize capsid increasing surface area buried at interfaces bringing cross-link–forming residues, initially ∼40 angstroms apart, close together. inner Prohead-II is negatively charged, suggesting that transition triggered electrostatically DNA packaging.