Structure of the K12 capsule containing 5,7-di-N-acetylacinetaminic acid from Acinetobacter baumannii isolate D36.
The repeat unit of the K12 capsular polysaccharide isolated from the Acinetobacter baumannii global clone 1 clinical isolate, D36, was elucidated by means of chemical and spectroscopical methods. The structure was shown to contain N-acetyl-D-galactosamine (D-GalpNAc), N-acetyl-D-fucosamine and N-acetyl-L-fucosamine linked together in the main chain, with the novel sugar, 5,7-diacetamido-3,5,7,9-tetradeoxy-L-glycero-L-altro-non-2-ulosonic acid (5,7-di-N-acetylacinetaminic acid or Aci5Ac7Ac), attached to D-GalpNAc as a side branch. This matched the sugar composition of the K12 capsule and the genetic content of the KL12 capsule gene cluster reported previously. D-FucpNAc was predicted to be the substrate for the initiating transferase, ItrB3, with the Wzy polymerase making a α-D-FucpNAc-(1 → 3)-D-GalpNAc linkage between the repeat units. The three glycosyltransferases encoded by KL12 are all retaining glycosyltransferases and were predicted to form specific linkages between the sugars in the K12 repeat unit.
School of Molecular Bioscience, The University of Sydney, Sydney, NSW 2006, Australia.
Johanna J
JJ
Kenyon
Department of Chemical Sciences, Complesso Universitario Monte Sant'Angelo, Napoli, Italy.
Alberto M
AM
Marzaioli
School of Molecular Bioscience, The University of Sydney, Sydney, NSW 2006, Australia ruth.hall@sydney.edu.au.
Ruth M
RM
Hall
Department of Chemical Sciences, Complesso Universitario Monte Sant'Angelo, Napoli, Italy.
Cristina
C
De Castro
D000116:Acetylgalactosamine / Q000737:chemistry / Q000302:isolation & purification; D040981:Acinetobacter baumannii / Q000737:chemistry* / Q000201:enzymology; D016667:Bacterial Capsules / Q000737:chemistry*; D002240:Carbohydrate Sequence; D005643:Fucose / Q000031:analogs & derivatives / Q000737:chemistry / Q000302:isolation & purification; D016695:Glycosyltransferases / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D012794:Sialic Acids / Q000737:chemistry / Q000302:isolation & purification
D012794:Sialic Acids; C050671:capsular polysaccharide K12; D005643:Fucose; C059377:N-acetylfucosamine; D016695:Glycosyltransferases; D000116:Acetylgalactosamine
Acinetobacter baumannii; K locus; KL12 gene cluster; acinetaminic acid; capsular polysaccharide