Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Host organism: Homo sapiens
Associated disease: pneumonia [ICD11:
CA40 
];
bacteremia [ICD11:
MA15.0 ];
meningitis [ICD11:
1D01 ];
urinary tract infections (UTI) [ICD11:
GC08 ];
infection due to Acinetobacter baumannii [ICD11:
XN8LS ]
NCBI PubMed ID: 19633088Publication DOI: 10.1128/JB.00647-09Journal NLM ID: 2985120RPublisher: American Society for Microbiology
Institutions: Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
We found that Acinetobacter baumannii contains a pgaABCD locus that encodes proteins that synthesize cell-associated poly-β-(1-6)-N-acetylglucosamine (PNAG). Both a mutant with an in-frame deletion of the pga locus (S1∆pga) and a transcomplemented strain (S1∆pga-c) of A. baumannii were constructed, and the PNAG production by these strains was compared using an immunoblot assay. Deleting the pga locus resulted in an A. baumannii strain without PNAG, and transcomplementation of the S1∆pga strain with the pgaABCD genes fully restored the wild-type PNAG phenotype. Heterologous expression of the A. baumannii pga locus in Escherichia coli led to synthesis of significant amounts of PNAG, while no polysaccharide was detected in E. coli cells harboring an empty vector. Nuclear magnetic resonance analysis of the extracellular polysaccharide material isolated from A. baumannii confirmed that it was PNAG, but notably only 60% of the glucosamine amino groups were acetylated. PCR analysis indicated that all 30 clinical A. baumannii isolates examined had the pga genes, and immunoblot assays indicated that 14 of the 30 strains strongly produced PNAG, 14 of the strains moderately to weakly produced PNAG, and 2 strains appeared to not produce PNAG. Deletion of the pga locus led to loss of the strong biofilm phenotype, which was restored by complementation. Confocal laser scanning microscopy studies combined with COMSTAT analysis demonstrated that the biovolume, mean thickness, and maximum thickness of 16-h and 48-h-old biofilms formed by wild-type and pga-complemented A. baumannii strains were significantly greater than the biovolume, mean thickness, and maximum thickness of 16-h and 48-h-old biofilms formed by the S1∆pga mutant strain. Biofilm-dependent production of PNAG could be an important virulence factor for this emerging pathogen that has few known virulence factors
Bacterial Proteins, Gene Expression Regulation, Bacterial, Acinetobacter baumannii, biofilms, beta-glucans
Structure type: homopolymer
Location inside paper: p. 5953, abstract
Trivial name: poly-β-1,6-GlcNAc (PGA), biofilm, poly-b-(1-6)-N-acetyl-D-glucosamine (PNAG), poly-β-N-acetyl-glucosamine (PNAG), PNAG, poly-N-acetylglucosamine, PNAG
Compound class: CPS, EPS, O-polysaccharide, glucan, polysaccharide
Contained glycoepitopes: IEDB_135813,IEDB_137340,IEDB_141807,IEDB_151531,IEDB_753248
Methods: 1H NMR, DNA techniques, NMR-1D, genetic methods, biochemical methods, immunoelectron microscopy, statistical analysis, bioinformatic analysis
Biosynthesis and genetic data: genetic data, biochemical data
NCBI Taxonomy refs (TaxIDs): 470Reference(s) to other database(s): GTC:G36952FI, GlycomeDB:
11210
Show glycosyltransferases
There is only one chemically distinct structure:
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