Document Detail

Identification of a novel sialic acid transporter in Haemophilus ducreyi.
MedLine Citation:
PMID:  16177350     Owner:  NLM     Status:  MEDLINE    
Haemophilus ducreyi, the causative agent of chancroid, produces a lipooligosaccharide (LOS) which terminates in N-acetyllactosamine. This glycoform can be further extended by the addition of a single sialic acid residue to the terminal galactose moiety. H. ducreyi does not synthesize sialic acid, which must be acquired from the host during infection or from the culture medium when the bacteria are grown in vitro. However, H. ducreyi does not have genes that are highly homologous to the genes encoding known bacterial sialic acid transporters. In this study, we identified the sialic acid transporter by screening strains in a library of random transposon mutants for those mutants that were unable to add sialic acid to N-acetyllactosamine-containing LOS. Mutants that reacted with the monoclonal antibody 3F11, which recognizes the terminal lactosamine structure, and lacked reactivity with the lectin Maackia amurensis agglutinin, which recognizes alpha2,3-linked sialic acid, were further characterized to demonstrate that they produced a N-acetyllactosamine-containing LOS by silver-stained sodium dodecyl sulfate-polyacrylamide gel electrophoresis and mass spectrometric analyses. The genes interrupted in these mutants were mapped to a four-gene cluster with similarity to genes encoding bacterial ABC transporters. Uptake assays using radiolabeled sialic acid confirmed that the mutants were unable to transport sialic acid. This study is the first report of bacteria using an ABC transporter for sialic acid uptake.
Deborah M B Post; Rachna Mungur; Bradford W Gibson; Robert S Munson
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Infection and immunity     Volume:  73     ISSN:  0019-9567     ISO Abbreviation:  Infect. Immun.     Publication Date:  2005 Oct 
Date Detail:
Created Date:  2005-09-22     Completed Date:  2005-11-28     Revised Date:  2013-06-07    
Medline Journal Info:
Nlm Unique ID:  0246127     Medline TA:  Infect Immun     Country:  United States    
Other Details:
Languages:  eng     Pagination:  6727-35     Citation Subset:  IM    
Buck Institute for Age Research, Novato, CA 94945, USA.
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MeSH Terms
Amino Sugars / immunology
Antibodies, Monoclonal / immunology
Bacterial Proteins / genetics*
Biological Transport / genetics
Chromosome Mapping
Gene Silencing
Haemophilus ducreyi / genetics,  immunology,  metabolism*
Lipopolysaccharides / chemistry
Mutagenesis, Insertional
N-Acetylneuraminic Acid / analysis,  metabolism*
Organic Anion Transporters / genetics*
Symporters / genetics*
Grant Support
Reg. No./Substance:
0/Amino Sugars; 0/Antibodies, Monoclonal; 0/Bacterial Proteins; 0/Lipopolysaccharides; 0/Organic Anion Transporters; 0/Symporters; 0/sialic acid transport proteins; 13000-25-4/lactosamine; 131-48-6/N-Acetylneuraminic Acid

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