Variation in the Complex Carbohydrate Biosynthesis Loci of Acinetobacter baumannii Genomes
Open Access
- 16 April 2013
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 8 (4), e62160
- https://doi.org/10.1371/journal.pone.0062160
Abstract
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.Keywords
This publication has 75 references indexed in Scilit:
- Genomic Analysis of the Multidrug-Resistant Acinetobacter baumannii Strain MDR-ZJ06 Widely Spread in ChinaAntimicrobial Agents and Chemotherapy, 2011
- Genome-wide recombination drives diversification of epidemic strains of Acinetobacter baumanniiProceedings of the National Academy of Sciences of the United States of America, 2011
- MEGA5: Molecular Evolutionary Genetics Analysis Using Maximum Likelihood, Evolutionary Distance, and Maximum Parsimony MethodsMolecular Biology and Evolution, 2011
- Biochemical Characterization of the O-Linked Glycosylation Pathway in Neisseria gonorrhoeae Responsible for Biosynthesis of Protein Glycans Containing N,N′-DiacetylbacillosamineBiochemistry, 2011
- Characterization of WbpB, WbpE, and WbpD and Reconstitution of a Pathway for the Biosynthesis of UDP-2,3-diacetamido-2,3-dideoxy-d-mannuronic Acid in Pseudomonas aeruginosaOnline Journal of Public Health Informatics, 2009
- Characterization of the lipopolysaccharide from a wbjE mutant of the serogroup O11 Pseudomonas aeruginosa strain, PA103Carbohydrate Research, 2008
- Flagellin Glycosylation in Pseudomonas aeruginosa PAK Requires the O-antigen Biosynthesis Enzyme WbpOOnline Journal of Public Health Informatics, 2008
- New insights into Acinetobacter baumannii pathogenesis revealed by high-density pyrosequencing and transposon mutagenesisJournal of Bone and Joint Surgery, 2007
- Vi Antigen Biosynthesis inSalmonella typhi: Characterization of UDP-N-acetylglucosamine C-6 Dehydrogenase (TviB) and UDP-N-acetylglucosaminuronic Acid C-4 Epimerase (TviC)Biochemistry, 2006
- CLUSTAL W: improving the sensitivity of progressive multiple sequence alignment through sequence weighting, position-specific gap penalties and weight matrix choiceNucleic Acids Research, 1994