Atomic-resolution characterization of actin-binding protein, cofilin-2, in complex with two nucleotide-states of F-actin, by magic angle spinning NMR spectroscopy

Abstract

Cofilin, an actin-binding protein, is critical for actin dynamics within the cell. Actin dynamics are responsible within the cell for many essential cellular processes such as cell motility, cell division and endocytosis. Cellular processes are related via actin-binding proteins and the nucleotide state of F-actin. Actin polymerization/depolymerization and filament severing have been extensively studied via X-ray fibre diffraction and cryo-electron microscopy; however, atomic-level structural information of actin associated proteins assembled on F-actin remained inaccessible. ☐ Here we report the first atomic-level resolution characterization of cofilin-2 assembled with F-actin in two nucleotide states (F-actin-ADP and F-actin-ADP-BeFx), by high-resolution magic-angle-spinning NMR. We have characterized the intermolecular interface of cofilin-2 on actin filaments in two nucleotide states. The results revealed remarkable spectral resolution enabling in-depth characterization of these systems. The MAS NMR approach presented here establishes the foundation for atomic-resolution structural analysis of a broad range of actin-associated proteins assembled on F-actin.