Linked Life Data

7885234

Source:http://linkedlifedata.com/resource/pubmed/id/7885234

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1995-4-10
pubmed:databankReference
pubmed:abstractText
Mycobacteria produce two siderophores, mycobactin and exochelin. Mycobacterium smegmatis mutants defective in the production of exochelin were isolated using agar medium containing chrome azural S for the sensitive detection of siderophores. Cosmids of genomic libraries from M. smegmatis and Mycobacterium bovis BCG were screened for complementation of the mutation. Subcloning of the complementing M. smegmatis cosmid identified a 4.3 kb fragment required for restoring exochelin biosynthesis. Sequencing of the DNA revealed four open reading frames whose genes were named fxuA, fxuB, fxuC, and fxbA. FxuA, FxuB, and FxuC share amino acid sequence homology with the iron permeases FepG, FepC, and FepD from Escherichia coli, respectively. Deletion analysis identified fxbA as the gene required to restore exochelin biosynthesis in our mutant. Although fxbA does not share amino acid sequence homology with any of the published sequences for siderophore biosynthetic genes, it does show limited homology with the phosphoribosylglycineamide formyltransferases (GAR enzymes) and methionyl-tRNA formyltransferase over a limited region of the sequence, suggesting that fxbA may code for an enzyme which adds a formyl group in the synthesis of exochelin. A fusion of fxbA with the E. coli lacZ gene demonstrated regulation of gene expression by iron. The ability of M. smegmatis mutants to produce mycobactin in the absence of exochelin supports the hypothesis that exochelin is not a precursor of mycobactin and suggests that the siderophores have independent biosynthetic pathways. In addition, complementation of the M. smegmatis mutant with the BCG cosmid restored the synthesis of the M. smegmatis exochelin, demonstrating the use of M. smegmatis as a surrogate host for analysis of exochelins from slow-growing mycobacteria.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0950-382X
pubmed:author
pubmed:issnType
Print
pubmed:volume
14
pubmed:geneSymbol
fxbA, fxuA, fxuB, fxuC
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
557-69
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:7885234-Amino Acid Sequence, pubmed-meshheading:7885234-Base Sequence, pubmed-meshheading:7885234-Biological Transport, Active, pubmed-meshheading:7885234-Cloning, Molecular, pubmed-meshheading:7885234-Cosmids, pubmed-meshheading:7885234-DNA, Bacterial, pubmed-meshheading:7885234-Escherichia coli, pubmed-meshheading:7885234-Gene Deletion, pubmed-meshheading:7885234-Genes, Bacterial, pubmed-meshheading:7885234-Genetic Complementation Test, pubmed-meshheading:7885234-Iron, pubmed-meshheading:7885234-Iron Chelating Agents, pubmed-meshheading:7885234-Molecular Sequence Data, pubmed-meshheading:7885234-Mutation, pubmed-meshheading:7885234-Mycobacterium, pubmed-meshheading:7885234-Mycobacterium bovis, pubmed-meshheading:7885234-Oxazoles, pubmed-meshheading:7885234-Peptides, Cyclic, pubmed-meshheading:7885234-Sequence Homology, Amino Acid
pubmed:year
1994
pubmed:articleTitle
Identification of genes involved in the sequestration of iron in mycobacteria: the ferric exochelin biosynthetic and uptake pathways.
pubmed:affiliation
Department of Microbiology and Immunology, Howard Hughes Medical Institute, Albert Einstein College of Medicine, Bronx, New York 10461.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.