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Biomedical subjects

S C Harrison

Publications and source records attributed to S C Harrison.

At least 163 records · Page 9Linked to original sources
PubMed1980

Protein interfaces and intersubunit bonding. The case of tomato bushy stunt virus.

An atomic model of the subunit of tomato bushy stunt virus (TBSV) has been constructed to fit an electron density map at 2.9 A resolution. Subunit interfaces show networks of polar residues forming H-bonds and salt bridges. The way in which alternative specific bonding geometries are built into a contact are described.

Hydrogen Bonding↗
PubMed1980

Molecular packing of nucleic acids in spherical viruses.

Electron microscopy and X-ray scattering show that double-stranded DNA is wound in a regular way in the heads of phage such as P22 and lambda. DNA is "pumped" into such heads, which may simply act as passive containers. In contrast, the protein-coat subunits of tomato bushy stunt virus have a flexibly tethered N-terminal domain that appears to be a major locus of interactions with the compactly folded RNA. Both modes of packaging permit considerable latitude in the detailed arrangement of the nucleic-acid chain, while still ensuring specific and efficient incorporation.

Bacteriophage lambda↗
PubMed1978

The structural organization of DNA packaged within the heads of T4 wild-type, isometric and giant bacteriophages.

We present electron microscopic and X-ray diffraction evidence concerning the structural organization of condensed DNA within a series of T4 bacteriophage with the following head morphologies: prolate (wild-type), isometric and giant (with greatly increased axial ratio). In all cases, the DNA helix segments are locally parallel and 27 A apart. For the giant particles, we show that the DNA forms a large coil whose axis is perpendicular to the axis of the phage tail. This evidence, combined with previous results from a series of isometric bacteriophages (Earnshaw and Harrison, 1977), leads to a model for the organization of condensed DNA that may apply to most dsDNA-containing bacteriophages.

Coliphages↗
PubMed1978

Hexagonal glycoprotein arrays from Sindbis virus membranes.

Freeze-etch electron microscopy of Sindbis virus and of glycoprotein arrays derived from Sindbis membranes by nonionic detergent treatment shows that the local geometry of glycoprotein-glycoprotein interaction does not depend on the presence of the nucleocapsid.

Freeze Etching↗
PubMed1977

DNA arrangement in isometric phage heads.

DNA is wound tightly into phage heads in such a way that it tends to form layers concentric with the rigid protein shell. In P22 and wild-type lambda, DNA completely fills the internal volume, with a highly uniform local packing of adjacent segments; in lambda deletion mutants containing less than a full genome, the local packing distance increases correspondingly.

Chromosome Deletion↗
PubMed1977

Tomato bushy stunt virus at 5.5-A resolution.

The coat of tomato bushy stunt virus is built from protein subunits having rigid domains connected by a flexible hinge. Two states of the hinge are present in the T=3 icosahedral structure. Each subunit has a binding site for RNA on its inner surface.

Nucleic Acid Conformation↗
PubMed1977

Glycosidase susceptibility: a probe for the distribution of glycoprotein oligosaccharides in Sindbis virus.

Intact Sindbis virus and Triton-solubilized viral glycoprotein were treated with alpha-mannosidase and with a preparation of mixed glycosidases from Diplococcus pneumoniae to probe the accesibility of carbohydrate units on the viral surface. The products of glycosidase attack on Triton-solubilized virus showed that mose carbohydrate units of the glycoproteins are good substrates for these enzymes. The relative resistance of most of the viral oligosaccharides in intact virus particles showed that much of the carbohydrate is not accessible to glycosidases, probably because it is not exposed at the viral surface. The only completely accessible carbohydrate units on Sindbis glycoproteins were the type A oligosaccharides of E2. This differential accessibility of Sindbis oligosaccharides is discussed in relation to the organization of the viral surface.

Fucose↗