Photocontrolled protein assembly for constructing programmed two-dimensional nanomaterials

Abstract

Precise self-assembly of proteins with structural heterogeneity, flexibility, and complexity into programmed arrays to mimic the exquisite architectures created by Nature is a great challenge for the development of protein-based functional nanomaterials. Herein, we present a strategy that integrates light stimuli and covalent coupling to prepare size-tunable two-dimensional (2D) protein nanostructures by remote photocontrol. Using Ru(bpy)₃²⁺ as a photosensitizer, stable protein one (SP1) was redesigned and self-assembled into nanosheets in the presence of ammonium persulfate (APS) through a rapid and efficient oxidative protein crosslinking reaction. In the design, only a serine-to-tyrosine mutation at position 98 was introduced into SP1 by combining computer simulation and genetic engineering for specific covalent coupling under white light illumination. The chemical and topographical specificities of the photosensitized crosslinking reaction allow control of the direction of protein assembly to form extended 2D nanosheets, which are packed in an orderly manner along the lateral surface of ring-shaped SP1S98Y. Notably, the growth of SP1 nanosheets exhibited isotropical characteristics and can be dynamically mediated by illumination time to achieve precise control of the size of the assembled architectures. The subsequent heat treatment further revealed the excellent thermostability of the 2D periodic SP1 nanostructures, which may find promising applications in the fabrication of various nanobiomaterials after functionalization. The present work demonstrates that the visible light-triggered crosslinking strategy is a facile and environmentally friendly method for constructing advanced protein architectures through hierarchical self-assembly.