AFM Imaging of Single Biomolecules and Their Interactions with Small Molecules

Single-Molecule Recognition of Biomolecular Interaction via Kelvin Probe Force Microscopy  

Jinsung Park, Jaemoon Yang, Gyudo Lee, Chang Young Lee, Sungsoo Na, Sang Woo Lee, Seungjoo Haam, Yong-Min Huh, Dae Sung Yoon, Kilho Eom*, Taeyun Kwon*

We report the scanning probe microscope (SPM)-based single-molecule recognition of biomolecular interactions between protein kinase and small ligands (i.e., ATP and Imatinib). In general, it is difficult to sense and detect the small ligands bound to protein kinase (at single-molecule resolution) using a conventional atomic force microscope (AFM) due to the limited resolution of conventional AFM for detecting the miniscule changes in molecular size driven by ligand binding. In this study, we have demonstrated that Kelvin probe force microscopy (KPFM) is able to articulate the surface potential of biomolecules interacting with ligands (i.e., the protein kinase–ATP interactions and inhibition phenomena induced by antagonistic molecules) in a label-free manner. Furthermore, measured surface potentials for biomolecular interactions enable quantitative descriptions on the ability of protein kinase to interact with small ligands such as ATP or antagonistic molecules. Our study sheds light on KPFM that allows the precise recognition of single-molecule interactions, which opens a new avenue for the design and development of novel molecular therapeutics.

Keywords: single molecule; biomolecular interactions; protein kinase; Kelvin probe force microscopy; label-free; surface potential

For the full text of the article, you may click here. This work was published at ACS Nano.