VIBRIO CHOLERAE NEURAMINIDASE
[NANH_VIBCH] Cleaves the terminal sialic acid (N-acetyl neuraminic acid) from carbohydrate chains in glycoproteins providing free sialic acid which can be used as carbon and energy sources. Sialidases have been suggested to be pathogenic factors in microbial infections. Facilitates cholera toxin binding to host intestinal epithelial cells by converting cell surface polysialogangliosides to GM1 monogangliosides.
Publication Abstract from PubMed
BACKGROUND: Vibrio cholerae neuraminidase is part of a mucinase complex which may function in pathogenesis by degrading the mucin layer of the gastrointestinal tract. The neuraminidase, which has been the target of extensive inhibitor studies, plays a subtle role in the pathology of the bacterium, by processing higher order gangliosides to GM1, the receptor for cholera toxin. RESULTS: We report here the X-ray crystal structure of V. cholerae neuraminidase at 2.3 A resolution. The 83 kDa enzyme folds into three distinct domains. The central catalytic domain has the canonical neuraminidase beta-propeller fold, and is flanked by two domains which possess identical legume lectin-like topologies but without the usual metal-binding loops. The active site has many features in common with other viral and bacterial neuraminidases but, uniquely, has an essential Ca2+ ion which plays a crucial structural role. CONCLUSIONS: The environment of the small intestine requires V. cholerae to secrete several adhesins, and it is known that its neuraminidase can bind to cell surfaces, and remain active. The unexpected lectin-like domains possibly mediate this attachment. These bacterial lectin folds represent additional members of a growing lectin superfamily.
Crystal structure of Vibrio cholerae neuraminidase reveals dual lectin-like domains in addition to the catalytic domain.,Crennell S, Garman E, Laver G, Vimr E, Taylor G Structure. 1994 Jun 15;2(6):535-44. PMID:7922030
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.