Salt-Switchable Artificial Cellulase Regulated by a DNA Aptamer

Abstract

A novel artificial cellulase was developed by conjugating a DNA aptamer to an endoglucanase catalytic domain, thereby substituting the natural carbohydrate-binding module. Circular dichroism spectroscopy and adsorption isotherm showed the binding motif of cellulose-binding DNA aptamer (CelApt) was G-quadruplex and stem-loop structures stabilized in the presence of salts, and CelApt binding preferred the amorphous region of the solid cellulose. By introducing the revealed salt-switchable cellulose-binding nature of CelApt into a catalytic domain of a cellulase, we created CelApt-catalytic domain conjugate possessing both controllable adsorption on the solid substrates and equal enzymatic activity to the wild-type cellulase. Thus potential use of a responsive DNA aptamer for biocatalysis at a solid surface was demonstrated.

On-chip structure-switching aptamer-modified magnetic nanobeads for the continuous monitoring of interferon-gamma ex vivo

“…Structure-switching molecules have demonstrated great potential in real-time biosensing 43 . When a suitably designed DNA aptamer binds to a specific analyte, it can change (switch) its structure, resulting in a measurable signal, and this effect can be used to design various sensing schemes to realize continuous monitoring 36 . Most biomaterials, such as antibodies, do not respond in any easily measurable way upon binding their target ligands.…”