Abstract: The presently-disclosed subject matter provides biosensors for detecting molecules of interest. The biosensors include a polypeptide capable of selectively-binding glucose, wherein the polypeptide molecule is selected from: an unnatural analogue of wild type glucose binding protein; a fragment of wild type glucose binding protein; and an unnatural analogue fragment of wild type glucose binding protein.

Abstract: The presently-disclosed subject matter is directed to biosensors for detecting molecules of interest, and systems and methods for using same. The biosensors include an antibody and a probe covalently-linked to the antibody. The antibody has an antigen-binding site that selectively binds the molecule of interest and a purine-binding site, which is at a location distinct from that of the antigen-binding site. The probe includes a purine molecule, which is covalently bound at the purine-binding site to the antibody, and a label linked to the purine molecule. Upon binding of the molecule of interest to the biosensor antigen-binding site, the biosensor undergoes a conformational change, which detectably alters a signal of the label such that the molecule of interest can be detected.

Abstract: The presently-disclosed subject matter provides biosensors for detecting molecules of interest. The biosensors comprise a polypeptide capable of selectively-binding glucose, wherein the polypeptide molecule is selected from: an unnatural analogue of wild type glucose binding protein; a fragment of wild type glucose binding protein; and an unnatural analogue fragment of wild type glucose binding protein.