Creation of Antigen-Dependent β-Lactamase Fusion Protein Tethered by Circularly Permuted Antibody Variable Domains.

Antibody-based molecular switches that are able to recognize a range of exogenous antigens can be highly useful as a versatile biosensor. However, regulating the catalytic activity of enzymes by antibodies is still hard to achieve. Here, we describe a design method of unique antibody variable region Fv introduced with two circular permutations, called Clampbody. By tethering the Clampbody to a circularly permuted TEM-1 β-lactamase (BLA), we successfully constructed a genetically encoded molecular switch Cbody-cpBLA that shows antigen-dependent catalytic activity.