Linked Life Data

19801685

Source:http://linkedlifedata.com/resource/pubmed/id/19801685

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
48
pubmed:dateCreated
2009-11-25
pubmed:abstractText
HslVU is a bacterial ATP-dependent protease distantly related to eukaryotic proteasomes consisting of hexameric HslU ATPase and dodecameric HslV protease. As a homolog of the 20 S proteasome beta-subunits, HslV also uses the N-terminal threonine as the active site residue. However, unlike the proteasome that has only 6 active sites among the 14 beta-subunits, HslV has 12 active sites that could potentially contribute to proteolytic activity. Here, by using a series of HslV dodecamers containing different numbers of active sites, we demonstrate that like the proteasome, HslV with only approximately 6 active sites is sufficient to support full catalytic activity. However, a further reduction of the number of active sites leads to a proportional decrease in activity. Using proteasome inhibitors, we also demonstrate that substrate-mediated stabilization of the HslV-HslU interaction remains unchanged until the number of the active sites is decreased to approximately 6 but is gradually compromised upon further reduction. These results with a mathematical model suggest HslVU utilizes no more than 6 active sites at any given time, presumably because of the action of HslU. These results also suggest that each ATP-bound HslU subunit activates one HslV subunit and that substrate bound to the HslV active site stimulates the HslU ATPase activity by stabilizing the HslV-HslU interaction. We propose this mechanism plays an important role in supporting complete degradation of substrates while preventing wasteful ATP hydrolysis in the resting state by controlling the interaction between HslV and HslU through the catalytic engagement of the proteolytic active sites.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1083-351X
pubmed:author
pubmed:issnType
Electronic
pubmed:day
27
pubmed:volume
284
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
33475-84
pubmed:dateRevised
2011-3-3
pubmed:meshHeading
pubmed-meshheading:19801685-Adenosine Triphosphate, pubmed-meshheading:19801685-Alanine, pubmed-meshheading:19801685-Amino Acid Substitution, pubmed-meshheading:19801685-Binding Sites, pubmed-meshheading:19801685-Catalysis, pubmed-meshheading:19801685-Electrophoresis, Polyacrylamide Gel, pubmed-meshheading:19801685-Endopeptidase Clp, pubmed-meshheading:19801685-Enzyme Assays, pubmed-meshheading:19801685-Escherichia coli Proteins, pubmed-meshheading:19801685-Hydrolysis, pubmed-meshheading:19801685-Kinetics, pubmed-meshheading:19801685-Models, Biological, pubmed-meshheading:19801685-Mutation, pubmed-meshheading:19801685-Peptides, pubmed-meshheading:19801685-Protein Binding, pubmed-meshheading:19801685-Protein Subunits, pubmed-meshheading:19801685-Spectrometry, Fluorescence, pubmed-meshheading:19801685-Substrate Specificity, pubmed-meshheading:19801685-Threonine
pubmed:year
2009
pubmed:articleTitle
HslVU ATP-dependent protease utilizes maximally six among twelve threonine active sites during proteolysis.
pubmed:affiliation
School of Biological Sciences, Seoul National University, Seoul 151-742, Korea.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't