Surface charge density measurement of a single protein molecule with a controlled orientation by AFM.

ABSTRACT: The spatial distribution of functional groups causes a charge distribution that often has a close relationship with its biofunctions. To understand them of the protein molecules, measurements of the charge distribution under physiological conditions are desired. Atomic force microscopy (AFM) has been utilized to measure the surface charge density by measuring the electric double layer (EDL) force caused by the overlap of the EDLs on the surfaces of the AFM tip and the biomolecule. Here, we demonstrated the surface charge density measurement of a single streptavidin (SA) protein molecule by the three-dimensional force mapping method based on frequency modulation AFM (FM-AFM). The SA has a strong affinity to biotin because of the electrostatic interactions between the molecules. Therefore, t

SUBMITTER: Yamamoto Y 

PROVIDER: S-EPMC8390862 | biostudies-literature | 2021 Jun

REPOSITORIES: biostudies-literature