Linked Life Data

1288619

Source:http://linkedlifedata.com/resource/pubmed/id/1288619

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1993-3-22
pubmed:abstractText
SecA is a single-chain, membrane-associated polypeptide (102 kDa) which functions as an essential component of the protein export machinery of Escherichia coli. SecA has been crystallized from ammonium sulfate as small, three-dimensional bipyramidal crystals (0.1 x 0.1 x 0.05 mm). These crystals did not demonstrate detectable diffraction of X-rays from rotating anode sources. For study by electron microscopy, individual crystals were cross-linked in glutaraldehyde and OsO4 solutions, dehydrated, embedded in epoxy resin, and sectioned normal to crystallographic axial directions inferred from the external morphology of the crystals. Fourier transformation of processed images of untilted thin sections stained with uranyl acetate and lead citrate show reflections extending to 31 A resolution. Diffraction data and reconstructed images of the projected density of the unit cell contents indicate that the bipyramidal SecA crystals belong to orthorhombic space group C222(1) with unit cell dimensions a = 414 A, b = 381 A, and c = 243 A. Filtered images and density maps of mutually orthogonal projections of the unit cell contents are consistent with a three-dimensional model in which the asymmetric unit contains eight SecA monomers. The large unit cell dimensions and packing of protein monomers suggest that SecA is crystallizing as an oligomer of either dimers or tetramers.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
1047-8477
pubmed:author
pubmed:issnType
Print
pubmed:volume
109
pubmed:geneSymbol
sec, secA
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
87-96
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:articleTitle
Electron microscopy of thin-sectioned three-dimensional crystals of SecA protein from Escherichia coli: structure in projection at 40 A resolution.
pubmed:affiliation
Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas 75235.
pubmed:publicationType
Journal Article