Structure of a polysaccharide from the lipopolysaccharide of Vibrio vulnificus clinical isolate YJ016 containing 2-acetimidoylamino-2-deoxy-L-galacturonic acid Sof’ya N. Senchenkova a , Alexander S. Shashkov a , Yuriy A. Knirel a, * , Consuelo Esteve b , Elena Alcaide b , Susana Merino c , Juan M. Tomás c a N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119991, Russia b Departamento de Microbiología y Ecología, Universidad de València, 46100 Burjassot, Valencia, Spain c Departamento Microbiología, Facultad Biología, Universidad de Barcelona, 08071 Barcelona, Spain article info Article history: Received 19 January 2009 Received in revised form 10 March 2009 Accepted 17 March 2009 Available online 24 March 2009 Keywords: Lipopolysaccharide Bacterial polysaccharide structure Di-N-acetylbacillosamine N-Acetimidoyl-L-galactosaminuronic acid Vibrio vulnificus abstract A polysaccharide isolated after mild acid degradation of the lipopolysaccharide of Vibrio vulnificus clinical isolate YJ016 was found to contain L-Fuc, D-GlcpNAc, 2,4-diacetamido-2,4,6-trideoxy-D-glucose (di-N- acetylbacillosamine, D-QuiNAc4NAc), and 2-acetimidoylamino-2-deoxy-L-galacturonic acid (L-GalNAmA). The last sugar derivative was confirmed by correlations for nitrogen-linked protons in 2D TOCSY and ROESY spectra measured in a H 2 O–D 2 O mixture. The following structure of the polysaccharide was estab- lished by 1 H and 13 C NMR spectroscopy, including 2D ROESY and 1 H, 13 C HMBC experiments: →3)-α-L-GalpNAmA-(1→3)-β-D-QuipNAc4NAc-(1 →3)-α-L-Fucp-(1→3)-α-D-GlcpNAc-(1→ 4 ↑ 1 β-D-GlcpNAc6Ac where the degree of 6-O-acetylation of the lateral b-GlcNAc residue is 70%. Ó 2009 Published by Elsevier Ltd. 1. Introduction Vibrio vulnificus, a bacterium from the c-group of Proteobacte- ria, is an etiologic agent of severe human infections acquired through wounds or contaminated seafood. It shares morphological and biochemical characteristics with other human vibrio patho- gens, including V. cholerae and V. parahaemolyticus. Based on phe- notypic characteristics and host range criteria, V. vulnificus isolates were primarily grouped into two biotypes: 1 indole + , orni- thine decarboxylase + (ODC + ) biotype 1 strains associated with pathogenicity in humans and indole  , ODC  biotype 2 strains that are pathogenic for eels. Later, this subdivision was questioned as indole  and ODC  strains were found to be pathogenic also for hu- mans and indole + and/or ODC + strains pathogenic for eels. In addi- tion, a third V. vulnificus biotype has been described in Israel; 2 it comprises cellobiose-negative strains isolated from patients who handled Saint Peter’s fish (Tilapia sp.). Therefore, all biotypes of V. vulnificus are potentially pathogenic for humans but biotype 1 strains are most frequently isolated from clinical specimens. 3 These opportunistic pathogens can attack immunocompromised patients and cause gastroenteritis (inflam- mation of mucous membranes of stomach and intestine), wound infections, and primary septicemia (spread of the microorganisms through the blood). Biotype 1 strains are the major cause of death from eating raw oysters, especially in people with liver damage. V. vulnificus YJ016 is a biotype 1 hospital isolate from Taiwan; 4,5 it contains two large chromosomes and a conjugative plasmid (pYJ016) completely sequenced. 6 In this work, we characterized chemically a polysaccharide from the lipopolysaccharide (LPS) of V. vulnificus YJ016 belonging to bio- type 1. Recently, we have elucidated the structure of a polysaccha- ride from the LPS of a biotype 2 (serotype E) isolate V. vulnificus CECT4602. 7 2. Results and discussion The lipopolysaccharide was isolated by phenol/water extraction of dried cells of V. vulnificus YJ016. A high-molecular-mass polysac- 0008-6215/$ - see front matter Ó 2009 Published by Elsevier Ltd. doi:10.1016/j.carres.2009.03.021 * Corresponding author. Tel.: +7 499 1376148; fax: +7 499 1355328. E-mail address: knirel@ioc.ac.ru (Y.A. Knirel). Carbohydrate Research 344 (2009) 1009–1013 Contents lists available at ScienceDirect Carbohydrate Research journal homepage: www.elsevier.com/locate/carres