PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 1605933

Ab initio phase determination for spherical viruses: parameter determination for spherical-shell models.

M S Chapman·J Tsao·M G Rossmann
View original source ↗Export metadata ↓

Abstract

The structure determination of canine parvovirus depended on the extension of phases calculated initially from a spherical-shell model [Tsao, Chapman, Wu, Agbandje, Keller & Rossmann (1992). Acta Cryst. B48, 75-88]. Such ab initio phasing holds the promise of obviating initial experimental phasing by isomorphous or molecular replacement, thereby expediting the structure determinations of spherical virus capsids. In this paper, it is shown how parameters such as radii, DNA density and particle positions may be determined and refined from diffraction data with sufficient precision to start phase extension from 20 A resolution for a virus of approximately 122 A radius.

Explore related subjects

CapsidDNA, ViralMathematicsModels, StructuralVirusesX-Ray DiffractionJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, Non-P.H.S.Research Support, U.S. Gov't, P.H.S.

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

M S Chapman, J Tsao, M G Rossmann. 1992-05-01. Ab initio phase determination for spherical viruses: parameter determination for spherical-shell models.. https://doi.org/10.1107/s0108767391013211

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2017

A directed evolution approach to select for novel Adeno-associated virus capsids on an HIV-1 producer T cell line.

A directed evolution approach was used to select for Adeno-associated virus (AAV) capsids that would exhibit more tropism toward an HIV-1 producer T cell line with the long-term goal of developing improved gene transfer vectors. A library of AAV variants was used to infect H9 T cells previously infected or uninfected by HIV-1 followed by AAV amplification with wild-type adenovirus. Six rounds of biological selection were performed, including negative selection and diversification after round three. The H9 T cells were successfully infected with all three wild-type viruses (AAV, adenovirus, and HIV-1). Four AAV cap mutants best representing the small number of variants emerging after six rounds of selection were chosen for further study. These mutant capsids were used to package an AAV vector and subsequently used to infect H9 cells that were previously infected or uninfected by HIV-1. A quantitative polymerase chain reaction assay was performed to measure cell-associated AAV genomes. Two of the four cap mutants showed a significant increase in the amount of cell-associated genomes as compared to wild-type AAV2. This study shows that directed evolution can be performed successfully to select for mutants with improved tropism for a T cell line in the presence of HIV-1.

Capsid↗
PubMed2014

Engineering adeno-associated viruses for clinical gene therapy.

Clinical gene therapy has been increasingly successful owing both to an enhanced molecular understanding of human disease and to progressively improving gene delivery technologies. Among these technologies, delivery vectors based on adeno-associated viruses (AAVs) have emerged as safe and effective and, in one recent case, have led to regulatory approval. Although shortcomings in viral vector properties will render extension of such successes to many other human diseases challenging, new approaches to engineer and improve AAV vectors and their genetic cargo are increasingly helping to overcome these barriers.

Capsid↗
PubMed1992

Structure of the U2 strain of tobacco mosaic virus refined at 3.5 A resolution using X-ray fiber diffraction.

The structure of the U2 strain of tobacco mosaic virus (TMV) has been determined by fiber diffraction methods at 3.5 A resolution, and refined by a combination of restrained least-squares and molecular dynamics methods to an R-factor of 0.096. The structure is extremely similar to that of the common strain of TMV, with the largest differences being in the protein loop that makes up the inner surface of the virus, and in the C-terminal region on the outer surface. Differences in the inner loop can be correlated with differences in the properties of the two viruses.

Capsid↗