Linked Life Data

9087916

Source:http://linkedlifedata.com/resource/pubmed/id/9087916

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1997-6-12
pubmed:abstractText
The maturation pathway of bacteriophage T4 capsid provides a model system for the study of largescale conformational changes, in that the precursor capsid progresses through four long-lived and widely differing states. The surface lattice first assembled (uncleaved/unexpanded state: hexagonal lattice constant, a = 11.8 nm) undergoes proteolytic cleavage (cleaved/unexpanded state), then expands (cleaved/ expanded state: a = 14.0 nm), and then binds accessory proteins. The most profound change, expansion, normally follows cleavage of the major capsid protein gp23 to gp23* (the 65-residue N-terminal "delta-domain" is removed), but can be induced in vitro in the absence of cleavage by treatment with 0.25 M guanidine-HCl (uncleaved/expanded state). We have studied this alternative pathway by negative staining electron microscopy of polyheads (tubular capsid variants). We find that uncleaved/expanded polyheads encompass four discrete states, called G1-G4, distinguished by their lattice constants of 12.6 nm (G1), 13.4 nm (G2), and 14.0 nm (G3, G4) and by the structures of their hexameric capsomers. Viewed in projection, the G4 capsomer differs from the cleaved/ expanded capsomer only in the presence of additional mass at one site per protomer. This mass correlates with the presence of the delta-domain, which translocates from the inner to the outer surface when the uncleaved lattice expands. Based on proximity of resemblance among these capsomers, we suggest that G1 to G4 represent a sequence of transitional states whose endpoint is G4. G1, G2, and G3 may correspond to intermediates that are too short-lived to be observed when the cleaved lattice expands, but are trapped by the retention of delta-domains at the interfaces between subunits in the uncleaved lattice.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
1047-8477
pubmed:author
pubmed:issnType
Print
pubmed:volume
118
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
73-82
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Multiple conformational states of the bacteriophage T4 capsid surface lattice induced when expansion occurs without prior cleavage.
pubmed:affiliation
Laboratory of Structural Biology, National Institute of Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland 20892-2717, USA.
pubmed:publicationType
Journal Article, Comparative Study