Expression of a Chlamydia anticarbohydrate single-chain antibody as a maltose binding fusion protein.

A single-chain antibody fragment has been constructed for an antibody that binds to the Chlamydia specific carbohydrate structure of the lipopolysaccharide. Single-chain protein was expressed and secreted into the periplasmic space of E. coli as a fusion protein with the maltose binding protein. The fusion protein was purified in one step by virtue of its ability to bind to maltose. In a sandwich ELISA, the eluted protein bound Chlamydia lipopolysaccharide, which demonstrates that the single-chain protein domain will function as part of a fusion protein. The expression of maltose binding fusion proteins into the periplasmic space could be used for production of other single-chain antibodies or protein fragments requiring appropriate folding and disulfide bond formation.