Structures of the O‐polysaccharides and classification of Proteus genomospecies 4, 5 and 6 into respective Proteus serogroups

• Published in: The FEBS journal 2005-11, Vol.272 (21), p.5536-5543
• Main Authors: Zych, Krystyna, Perepelov, Andrei V., Siwiňska, Małgorzata, Knirel, Yuriy A., Sidorczyk, Zygmunt
• Format: Article
• Language: English
• Subjects: 3‐acetamido‐3,6‐dideoxy‐d‐glucose; Antibodies - immunology; Biochemistry; Carbohydrate Sequence; Classification; Magnetic Resonance Spectroscopy; Molecular Sequence Data; Molecular structure; O Antigens - chemistry; O‐antigen; O‐serogroup; Proteus; Proteus - chemistry; Proteus - classification; serological classification; Spectrum analysis; Sugar
• ISSN: 1742-464X; 1742-4658
• DOI: 10.1111/j.1742-4658.2005.04958.x

An acidic branched O‐polysaccharide was isolated by mild acid degradation of the lipopolysaccharide (LPS) of Proteus genomospecies 4 and studied by sugar and methylation analyses along with 1H and 13C NMR spectroscopy, including 2D COSY, TOCSY, ROESY and H‐detected 1H,13C HSQC experiments. The following structure of the pentasaccharide repeating unit of the O‐polysaccharide was established, which is unique among Proteus polysaccharide structures: where Qui3NAc stands for 3‐acetamido‐3,6‐dideoxyglucose. Based on the O‐polysaccharide structure and serological data, we propose classifying Proteus genomospecies 4 into a new, separate Proteus serogroup, O56. A weak cross‐reactivity of Proteus genomospecies 4 antiserum with LPS of Providencia stuartii O18 and Proteus vulgaris OX2 was observed and is discussed in view of a similarity of the O‐polysaccharide structures. Structural and serological investigations showed that Proteus genomospecies 5 and 6 should be classified into the existing Proteus serogroups O8 and O69, respectively.