EXPRESSION AND BIOLOGICAL-ACTIVITY OF GENETIC FUSIONS BETWEEN MALE, THE MALTOSE-BINDING PROTEIN FROM ESCHERICHIA-COLI AND PORTIONS OF CD4, THE T-CELL RECEPTOR OF THE AIDS VIRUS

Hybrid molecules between MalE, the periplasmic maltose binding protein of Escherichia coli, and CD4, the human T-lymphocyte receptor for the AIDS virus HIV, have been constructed and purified. We show that CD4 can be fused as multiple repeats to both ends of a single MalE molecul e. Hybrid proteins are exported into the periplasm of bacteria, bind m onoclonal antibodies directed against CD4, bind HIV gp160, and inhibit HIV binding to CD4(+) cells. MalE has been used as a scaffold to graf t portions of CD4. Deletion analysis allowed to define a minimal struc tural domain which folds in a way which is compatible with its biologi cal activity. This minimal part was used to design compact hybrid mole cules in which CD4 was inserted internally into MalE. (C) 1996 Academi c Press, Inc.