Protein Needles Designed to Self‐Assemble through Needle Tip Engineering

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2022-03, Vol.18 (10), p.e2106401-n/a
• Main Authors: Kikuchi, Kosuke, Fukuyama, Tatsuya, Uchihashi, Takayuki, Furuta, Tadaomi, Maeda, Yusuke T., Ueno, Takafumi
• Format: Article
• Language: English
• Subjects: 2D assembly; Assemblies; Assembly; Atomic force microscopy; high‐speed atomic force microscopy; Lattices; Mica; Monte Carlo simulation; Nanotechnology; protein assembly; protein needle; Proteins
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202106401

The dynamic process of formation of protein assemblies is essential to form highly ordered structures in biological systems. Advances in structural and synthetic biology have led to the construction of artificial protein assemblies. However, development of design strategies exploiting the anisotropic shape of building blocks of protein assemblies has not yet been achieved. Here, the 2D assembly pattern of protein needles (PNs) is controlled by regulating their tip‐to‐tip interactions. The PN is an anisotropic needle‐shaped protein composed of β‐helix, foldon, and His‐tag. Three different types of tip‐modified PNs are designed by deleting the His‐tag and foldon to change the protein–protein interactions. Observing their assembly by high‐speed atomic force microscopy (HS‐AFM) reveals that PN, His‐tag deleted PN, and His‐tag and foldon deleted PN form triangular lattices, the monomeric state with nematic order, and fiber assemblies, respectively, on a mica surface. Their assembly dynamics are observed by HS‐AFM and analyzed by the theoretical models. Monte Carlo (MC) simulations indicate that the mica‐PN interactions and the flexible and multipoint His‐tag interactions cooperatively guide the formation of the triangular lattice. This work is expected to provide a new strategy for constructing supramolecular protein architectures by controlling directional interactions of anisotropic shaped proteins. The 2D self‐assembly of anisotropic protein needles (PNs) are modulated by modifying the needle tip structures. High‐speed atomic force microscopy observations of PN deposited on a mica surface reveval the formation of triangle lattices, the monomeric state with nematic order, and straight fibers depending on the tip structures of PN.