Major Subunit, CfaB, of Colonization Factor Antigen I from Enterotoxigenic Escherichia coli Is a Glycosphingolipid Binding Protein

• Published in: Infection and Immunity 2006-06, Vol.74 (6), p.3488-3497
• Main Authors: Jansson, Lena, Tobias, Joshua, Lebens, Michael, Svennerholm, Ann-Mari, Teneberg, Susann
• Format: Article
• Language: English
• Subjects: Bacterial; Bacteriology; Biological and medical sciences; Carrier Proteins; Carrier Proteins - metabolism; chemistry; Escherichia coli; Escherichia coli Proteins; Escherichia coli Proteins - metabolism; Fimbriae; Fimbriae Proteins; Fimbriae Proteins - chemistry; Fimbriae Proteins - metabolism; Fimbriae, Bacterial; Fundamental and applied biological sciences. Psychology; Glycosphingolipids; Glycosphingolipids - metabolism; Humans; metabolism; Microbiology; Microbiology in the medical area; Mikrobiologi inom det medicinska området; Miscellaneous; Molecular Pathogenesis; Protein Subunits
• ISSN: 0019-9567; 1098-5522
• DOI: 10.1128/IAI.02006-05

Bacterial adherence to mucosal surfaces is an important virulence trait of pathogenic bacteria. Adhesion of enterotoxigenic Escherichia coli (ETEC) to the intestine is mediated by a number of antigenically distinct colonization factors (CFs). One of the most common CFs is CFA/I. This has a fimbrial structure composed of a major repeating subunit, CfaB, and a single tip subunit, CfaE. The potential carbohydrate recognition by CFA/I was investigated by binding CFA/I-fimbriated bacteria and purified CFA/I fimbriae to a large number of variant glycosphingolipids separated on thin-layer chromatograms. For both fimbriated bacteria and purified fimbriae, specific interactions could be identified with a number of nonacid glycosphingolipids. These included glucosylceramide, lactosylceramide with phytosphingosine and/or hydroxy fatty acids, neolactotetraosylceramide, gangliotriaosylceramide, gangliotetraosylceramide, the H5 type 2 pentaglycosylceramide, the Lea-5 glycosphingolipid, the Lex-5 glycosphingolipid, and the Ley-6 glycosphingolipid. These glycosphingolipids were also recognized by recombinant E. coli expressing CFA/I in the absence of tip protein CfaE, as well as by purified fimbriae from the same strain. This demonstrates that the glycosphingolipid-binding capacity of CFA/I resides in the major CfaB subunit.