Linked Life Data

9254634

Source:http://linkedlifedata.com/resource/pubmed/id/9254634

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
33
pubmed:dateCreated
1997-9-15
pubmed:abstractText
SKC1, a 160-residue potassium channel with two putative transmembrane (TM) segments was recently identified from Streptomyces lividans. Its high levels of expression, small size, and ease of purification make SKC1 an ideal candidate for high-resolution structural studies. We have initiated the structural characterization of this channel by assessing its oligomeric behavior, stability in detergent, general hydrodynamic properties, and preliminary secondary structure content. SKC1 was readily expressed and purified to homogeneity by sequential metal-chelate and gel filtration chromatography. Standard SDS-PAGE, together with chemical cross-linking analysis indicated that SKC1 behaves as a tightly associated tetramer even in the presence of SDS. Using a gel shift assay to assess its oligomeric state, we determined that SKC1 is stable as a tetramer in most detergents and can be maintained in nonionic detergent solutions for extended periods of time. The tetramer is also stable at relatively high temperatures, with an oligomer-to-monomer transition occurring at approximately 65 degrees C. The Stokes radius of the micellar complex is 5 nm as determined from gel filtration chromatography of SKC1 in dodecyl maltoside. Preliminary estimations of secondary structure from CD spectroscopy showed that the channel exists mostly in alpha-helical conformation, with more than 50% alpha-helical, close to 20% beta-sheet, 10% beta-turn, and about 15% unassigned or random coil. These results are consistent with the idea that a bundle of alpha-helices forming a tetramer around the ion-conductive pathway is the common structural motif for members of the voltage-dependent channel superfamily.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
19
pubmed:volume
36
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
10343-52
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Structural dynamics of the Streptomyces lividans K+ channel (SKC1): oligomeric stoichiometry and stability.
pubmed:affiliation
Department of Molecular Physiology and Biological Physics, University of Virginia Health Sciences Center, Charlottesville, Virginia 22906-0011, USA.
pubmed:publicationType
Journal Article