A novel FRET approach for in situ investigation of cellulase-cellulose interaction

A novel real-time in situ detection method for the investigation of cellulase-cellulose interactions based on fluorescence resonance energy transfer (FRET) has been developed. FRET has been widely used in biological and biophysical fields for studies related to proteins, nucleic acids, and small biological molecules. Here, we report the efficient labeling of carboxymethyl cellulose (CMC) with donor dye 5-(aminomethyl)fluorescein and its use as a donor in a FRET assay together with an Alexa Fluor 594 (AF594, acceptor)-cellulase conjugate as acceptor. This methodology was successfully employed to investigate the temperature dependency of cellulase binding to cellulose at a molecular level by monitoring the fluorescence emission change of donor (or acceptor) in a homogeneous liquid environment. It also provides a sound base for ongoing cellulase-cellulose study using cellulosic fiber.