Linked Life Data

17553803

Source:http://linkedlifedata.com/resource/pubmed/id/17553803

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
31
pubmed:dateCreated
2007-7-30
pubmed:abstractText
ATP binding to the PAN-ATPase complex in Archaea or the homologous 19 S protease-regulatory complex in eukaryotes induces association with the 20 S proteasome and opening of its substrate entry channel, whereas ATP hydrolysis allows unfolding of globular substrates. To clarify the conformational changes associated with ATP binding and hydrolysis, we used protease sensitivity to monitor the conformations of the PAN ATPase from Methanococcus jannischii. Exhaustive trypsin treatment of PAN generated five distinct fragments, two of which differed when a nucleotide (either ATP, ATP gamma S, or ADP) was bound. Surprisingly, the nucleotide concentrations altering protease sensitivity were much lower (K(a) 20-40 microm) than are required for ATP-dependent protein breakdown by the PAN-20S proteasome complex (K(m) approximately 300-500 microm). Unlike trypsin, proteinase K yielded several fragments that differed in the ATP gamma S and ADP-bound forms, and thus revealed conformational transitions associated with ATP hydrolysis. Mapping the fragments generated by each revealed that nucleotide binding and hydrolysis induce local conformational changes, affecting the Walker A and B nucleotide-binding motif, as well as global changes extending to its carboxyl terminus. The location and overlap of the fragments also suggest that the conformation of the six subunits is not identical, probably because they do not all bind ATP simultaneously. Partial nucleotide occupancy was supported by direct assays, which demonstrated that, at saturating conditions, only four nucleotides are bound to hexameric PAN. Using the protease protection maps, we modeled the conformational changes associated with ATP binding and hydrolysis in PAN based on the x-ray structures of the homologous AAA ATPase, HslU.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
3
pubmed:volume
282
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
22921-9
pubmed:dateRevised
2010-12-3
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
ATP-induced structural transitions in PAN, the proteasome-regulatory ATPase complex in Archaea.
pubmed:affiliation
Program in Biology and Biomedical Sciences, Harvard Medical School, Boston, MA 02115, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, N.I.H., Extramural