STRUCTURE OF A PERTUSSIS TOXIN SUGAR COMPLEX AS A MODEL FOR RECEPTOR-BINDING

Pertussis toxin is an exotoxin from the bacterium Bordetella pertussis which is important the pathogenesis of whooping cough and the generat ion of a protective immune response. The diverse biological activities of the toxin depend on its ability to recognize carbohydrate-containi ng receptors on a wide variety of eukaryotic cells. We present here th e crystal structure of pertussis toxin complexed with a soluble oligos accharide from transferrin. Binding sites for the terminal sialic acid -galactose moiety are revealed on both subunits SZ and S3 of the B-oli gomer. Identification of amino acid residues involved in receptor bind ing will improve the design of genetically inactivated toxins for use in new acellular whooping cough vaccines.