Linked Life Data

15882410

Source:http://linkedlifedata.com/resource/pubmed/id/15882410

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2005-5-10
pubmed:abstractText
In addition to being the major citric acid cycle aconitase in Escherichia coli the aconitase B protein (AcnB) is also a post-transcriptional regulator of gene expression. The AcnB proteins represent a distinct branch of the aconitase superfamily that possess a HEAT-like domain (domain 5). The HEAT domains of other proteins are implicated in protein:protein interactions. Gel filtration analysis has now shown that cell-free extracts contain high-molecular-weight species of AcnB. Furthermore, in vitro and in vivo protein interaction experiments have shown that AcnB forms homodimers. Addition of the iron chelator bipyridyl to cultures inhibited the dimer-dependent readout from an AcnB bacterial two-hybrid system. A similar response was observed with a catalytically inactive AcnB variant, AcnB(C769S), suggesting that the monomer-dimer transition is not mediated by the state of the AcnB iron-sulphur cluster. The iron-responsive interacting unit was accordingly traced to the N-terminal region (domains 4 and 5) of the AcnB protein, and not to domain 3 that houses the iron-sulphur cluster. Thus, it was shown that a polypeptide containing AcnB N-terminal domains 5 and 4 (AcnB5-4) interacts with a second AcnB5-4 to form a homodimer. AcnB has recently been shown to initiate a regulatory cascade controlling flagella biosynthesis in Salmonella enterica by binding to the ftsH transcript and inhibiting the synthesis of the FtsH protease. A plasmid encoding AcnB5-4 complemented the flagella-deficient phenotype of a S. enterica acnB mutant, and the isolated AcnB5-4 polypeptide specifically recognized and bound to the ftsH transcript. Thus, the N-terminal region of AcnB is necessary and sufficient for promoting the formation of AcnB dimers and also for AcnB binding to target mRNA. Furthermore, the relative effects of iron on these processes provide a simple iron-mediated dimerization mechanism for switching the AcnB protein between catalytic and regulatory roles.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0950-382X
pubmed:author
pubmed:issnType
Print
pubmed:volume
56
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1149-58
pubmed:dateRevised
2010-10-8
pubmed:meshHeading
pubmed-meshheading:15882410-ATP-Dependent Proteases, pubmed-meshheading:15882410-Aconitate Hydratase, pubmed-meshheading:15882410-Bacterial Proteins, pubmed-meshheading:15882410-Dimerization, pubmed-meshheading:15882410-Electrophoretic Mobility Shift Assay, pubmed-meshheading:15882410-Escherichia coli, pubmed-meshheading:15882410-Escherichia coli Proteins, pubmed-meshheading:15882410-Flagella, pubmed-meshheading:15882410-Genes, Reporter, pubmed-meshheading:15882410-Genetic Complementation Test, pubmed-meshheading:15882410-Iron, pubmed-meshheading:15882410-Membrane Proteins, pubmed-meshheading:15882410-Models, Molecular, pubmed-meshheading:15882410-Mutation, pubmed-meshheading:15882410-Protein Binding, pubmed-meshheading:15882410-Protein Structure, Tertiary, pubmed-meshheading:15882410-RNA, Bacterial, pubmed-meshheading:15882410-RNA, Messenger, pubmed-meshheading:15882410-Salmonella enterica, pubmed-meshheading:15882410-beta-Galactosidase
pubmed:year
2005
pubmed:articleTitle
Switching aconitase B between catalytic and regulatory modes involves iron-dependent dimer formation.
pubmed:affiliation
The Krebs Institute for Biomolecular Research, Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't