Switch to
Predicate | Object |
---|---|
rdf:type | |
lifeskim:mentions | |
pubmed:issue |
2
|
pubmed:dateCreated |
1988-6-29
|
pubmed:abstractText |
The bacteriophage T7 tail complex consists of a conical tail-tube surrounded by six kinked tail-fibers, which are oligomers of the viral protein gp17 (Mr 61,400). We have derived a molecular model for the tail-fiber by integrating secondary structure predictions with ultrastructural information obtained by correlation averaging of electron micrographs of negatively stained tail complexes. This model has been further refined by high-resolution scanning transmission electron microscopy of purified fibers, both negatively stained and unstained. Mass measurements made from the latter images establish that the fiber is a trimer of gp17. The proximal half-fiber is a uniform rod, about 2.0 nm in diameter and 16.4 nm long, which we infer to be a triple-stranded coiled-coil, containing three copies of an alpha-helical domain of about 117 residues, starting at Phe151. The distal half-fiber is 15.5 nm long, and is made up of four globules, 3.1 to 4.8 nm in diameter, in rigid linear array: it contains the carboxy-terminal halves (residues approximately 268 to 553) of the constituent gp17 chains, arranged with 3-fold symmetry around its long axis. The amino-terminal domains (residues 1 to 149) link the fiber to the tail-tube. We conclude that the three gp17 chains are quasi-equivalent in the proximal half-fiber, equivalent in the distal half-fiber, and non-equivalent in the kink region that separates the two half-fibers: such localized non-equivalence may represent a general mechanism for the formation of kinked joints in segmented homo-oligomeric proteins.
|
pubmed:language |
eng
|
pubmed:journal | |
pubmed:citationSubset |
IM
|
pubmed:chemical | |
pubmed:status |
MEDLINE
|
pubmed:month |
Mar
|
pubmed:issn |
0022-2836
|
pubmed:author | |
pubmed:issnType |
Print
|
pubmed:day |
20
|
pubmed:volume |
200
|
pubmed:owner |
NLM
|
pubmed:authorsComplete |
Y
|
pubmed:pagination |
351-65
|
pubmed:dateRevised |
2008-11-21
|
pubmed:meshHeading |
pubmed-meshheading:3259634-Amino Acid Sequence,
pubmed-meshheading:3259634-Hot Temperature,
pubmed-meshheading:3259634-Macromolecular Substances,
pubmed-meshheading:3259634-Microscopy, Electron, Scanning,
pubmed-meshheading:3259634-Protein Conformation,
pubmed-meshheading:3259634-Receptors, Virus,
pubmed-meshheading:3259634-T-Phages,
pubmed-meshheading:3259634-Viral Proteins
|
pubmed:year |
1988
|
pubmed:articleTitle |
Molecular substructure of a viral receptor-recognition protein. The gp17 tail-fiber of bacteriophage T7.
|
pubmed:affiliation |
Laboratory of Physical Biology, National Institute of Arthritis, Bethesda, MD 20892.
|
pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, Non-P.H.S.
|