Linked Life Data

20704181

Source:http://linkedlifedata.com/resource/pubmed/id/20704181

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
37
pubmed:dateCreated
2010-9-14
pubmed:abstractText
Under iron limitation, the Gram-positive bacterium Streptomyces coelicolor A3(2) excretes three siderophores of the hydroxamate type: desferrioxamine B, desferrioxamine E, and coelichelin. These sequester iron from insoluble ferric hydroxides, and the resulting ferric complexes are believed to be transported into the cell via siderophore-binding proteins (SBPs) associated with ATP-binding cassette (ABC) transporters. Previous studies indicated that some of the genes in the desferrioxamine (des) and coelichelin (cch) biosynthetic clusters encode ABC transporter components required for efficient uptake of ferrioxamine E and ferricoelichelin, respectively, and a third ABC transporter gene cluster (cdt), not associated with siderophore biosynthesis genes, was implicated in the import of ferrioxamine B. In this study, the putative SBPs associated with these three gene clusters, DesE, CchF, and CdtB, were recombinantly overproduced in Escherichia coli and purified to homogeneity, and their binding affinity for cognate siderophores and noncognate siderophores was examined using fluorescence and circular dichroism spectroscopy. DesE was found to bind all of the ferric-tris-hydroxamates tested except ferricoelichelin, while CchF was found to bind only ferricoelichelin efficiently, providing further evidence that the cch cluster is a complete siderophore biosynthesis-export-uptake gene cluster. The picture was more complicated for CdtB, because it was found to be unstable in solution but was found to bind both ferrioxamine B and ferricoelichelin with high affinity. This was surprising because the cch cluster was previously reported to be necessary for efficient ferricoelichelin uptake. The remarkable specificity of the DesE and CchF proteins for different ferric-tris-hydroxamates raises intriguing questions about the molecular basis of their substrate specificity.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/ATP-Binding Cassette Transporters, http://linkedlifedata.com/resource/pubmed/chemical/Carrier Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Deferoxamine, http://linkedlifedata.com/resource/pubmed/chemical/Ferric Compounds, http://linkedlifedata.com/resource/pubmed/chemical/Hydroxamic Acids, http://linkedlifedata.com/resource/pubmed/chemical/Iron, http://linkedlifedata.com/resource/pubmed/chemical/Oligopeptides, http://linkedlifedata.com/resource/pubmed/chemical/Peptides, Cyclic, http://linkedlifedata.com/resource/pubmed/chemical/Siderophores, http://linkedlifedata.com/resource/pubmed/chemical/coelichelin, http://linkedlifedata.com/resource/pubmed/chemical/ferric hydroxide, http://linkedlifedata.com/resource/pubmed/chemical/ferrioxamine B, http://linkedlifedata.com/resource/pubmed/chemical/ferrioxamine E, http://linkedlifedata.com/resource/pubmed/chemical/iron (III) hydroxamate
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1520-4995
pubmed:author
pubmed:issnType
Electronic
pubmed:day
21
pubmed:volume
49
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
8033-42
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Distinct extracytoplasmic siderophore binding proteins recognize ferrioxamines and ferricoelichelin in Streptomyces coelicolor A3(2).
pubmed:affiliation
Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't