A 76-AMINO ACID DISULFIDE LOOP IN THE YERSINIA-PSEUDOTUBERCULOSIS INVASIN PROTEIN IS REQUIRED FOR INTEGRIN RECEPTOR RECOGNITION

作者：LEONG JM; MORRISSEY PE; ISBERG RR

来源：Journal of Biological Chemistry, 1993, 268(27): 20524-20532.

The Yersinia pseudotuberculosis invasin protein is a 986-amino acid protein that promotes bacterial penetration into mammalian cells by avidly binding multiple beta1-chain integrins. A 192-amino acid carboxyl-terminal domain of invasin was previously shown to be sufficient for binding. Evidence is presented here that a 76-amino acid disulfide loop in the integrin binding domain of invasin is required for invasin-mediated cell binding and entry. Bacterial mutants that were altered at either of 2 cysteine residues in the binding domain of invasin were completely defective for entry. Purified invasin protein derivatives altered at either of these cysteines, in contrast to the wild-type invasin, did not promote either cell binding or penetration. Analysis of proteolytic products of invasin in the presence or absence of reducing agent provided evidence of an intrachain disulfide bond near the carboxyl terminus of the protein. Alkylation of invasin derivatives with [H-3]iodoacetate indicated that these 2 cysteines were normally disulfide-bonded. A treatment that resulted in the maximal reduction of the disulfide bond also resulted in maximal loss of cell attachment activity. These results indicate that the 76-amino acid disulfide loop at the carboxyl terminus of invasin is required for recognition by integrins.

• 出版日期1993-9-25