Variation in the complex carbohydrate biosynthesis loci of Acinetobacter baumannii genomes
Kenyon, Johanna J. & Hall, Ruth M. (2013) Variation in the complex carbohydrate biosynthesis loci of Acinetobacter baumannii genomes. PLoS ONE, 8(4), e62160.
Extracellular polysaccharides are major immunogenic components of the bacterial cell envelope. However, little is known about their biosynthesis in the genus Acinetobacter, which includes A. baumannii, an important nosocomial pathogen. Whether Acinetobacter sp. produce a capsule or a lipopolysaccharide carrying an O antigen or both is not resolved. To explore these issues, genes involved in the synthesis of complex polysaccharides were located in 10 complete A. baumannii genome sequences, and the function of each of their products was predicted via comparison to enzymes with a known function. The absence of a gene encoding a WaaL ligase, required to link the carbohydrate polymer to the lipid A-core oligosaccharide (lipooligosaccharide) forming lipopolysaccharide, suggests that only a capsule is produced. Nine distinct arrangements of a large capsule biosynthesis locus, designated KL1 to KL9, were found in the genomes. Three forms of a second, smaller variable locus, likely to be required for synthesis of the outer core of the lipid A-core moiety, were designated OCL1 to OCL3 and also annotated. Each K locus includes genes for capsule export as well as genes for synthesis of activated sugar precursors, and for glycosyltransfer, glycan modification and oligosaccharide repeat-unit processing. The K loci all include the export genes at one end and genes for synthesis of common sugar precursors at the other, with a highly variable region that includes the remaining genes in between. Five different capsule loci, KL2, KL6, KL7, KL8 and KL9 were detected in multiply antibiotic resistant isolates belonging to global clone 2, and two other loci, KL1 and KL4, in global clone 1. This indicates that this region is being substituted repeatedly in multiply antibiotic resistant isolates from these clones.
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|Item Type:||Journal Article|
|Keywords:||Polysaccharide, Acinetobacter baumannii, K locus, OC locus, Genetic variation, Genome, Gene annotation, Clone, Bacterial pathogen, Hospital-acquired infection|
|Subjects:||Australian and New Zealand Standard Research Classification > BIOLOGICAL SCIENCES (060000) > BIOCHEMISTRY AND CELL BIOLOGY (060100) > Bioinformatics (060102)
Australian and New Zealand Standard Research Classification > BIOLOGICAL SCIENCES (060000) > MICROBIOLOGY (060500)
Australian and New Zealand Standard Research Classification > BIOLOGICAL SCIENCES (060000) > MICROBIOLOGY (060500) > Microbial Genetics (060503)
|Divisions:||Current > Schools > School of Biomedical Sciences
Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
|Copyright Owner:||Copyright 2013 Kenyon, Hall|
|Copyright Statement:||This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.|
|Deposited On:||01 Dec 2015 22:46|
|Last Modified:||08 Dec 2015 04:55|
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