Novel lipoarabinomannan-like lipoglycan (CdiLAM) contributes to the adherence of Corynebacterium diphtheriae to epithelial cells.
The genus Corynebacterium is part of the phylogenetic group nocardioform actinomycetes. Members of this group have a characteristic cell envelope structure composed primarily of branched long-chain lipids, termed mycolic acids, and a rich number of lipoglycans such as lipoarabinomanans (LAM) and lipomannans. In this study, we identified a novel LAM variant isolated from Corynebacterium diphtheriae named CdiLAM. The key structural features of CdiLAM are a linear alpha-1-->6-mannan with side chains containing 2-linked alpha-D-Manp and 4-linked alpha-D-Araf residues. The polysaccharide backbone is linked to a phosphatidylinositol anchor. In contrast to the LAMs of other members of actinomycetales, CdiLAM presents an unusual substitution at position 4 of alpha-1-->6-mannan backbone by alpha-D-Araf. Unlike the non-fimbrial adhesin 62-72p, CdiLAM did not function as a hemagglutinin to human red blood cells. Experimental evidences pointed to CdiLAM as an adhesin of C. diphtheriae to human respiratory epithelial cells, thereby, contributing to the pathogenesis of diphtheria.
Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil. lilian.moreira@stjude.org
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Moreira
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Mattos-Guaraldi
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Andrade
D018829:Adhesins, Bacterial / Q000737:chemistry / Q000378:metabolism*; D001422:Bacterial Adhesion; D002240:Carbohydrate Sequence; D003353:Corynebacterium diphtheriae / Q000737:chemistry* / Q000502:physiology*; D004847:Epithelial Cells / Q000382:microbiology*; D004912:Erythrocytes / Q000382:microbiology; D006384:Hemagglutination; D006801:Humans; D008070:Lipopolysaccharides / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010716:Phosphatidylinositols / Q000737:chemistry
D018829:Adhesins, Bacterial; D008070:Lipopolysaccharides; D010716:Phosphatidylinositols