Proteins designed to bind to a specific surface
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Proteins designed to bind to a specific surface
PEG, POM started to disperse among the water molecules uniformly, meaning its solubility enhanced considerably. Qigang Wang of Tongji University, China, highlights the significance of this work: “It is tricky to predict the water solubilities of macromolecules, as they do not always obey the ‘like dissolves like’ principle and empirical rules valid for small molecules. The advanced spectroscopy techniques and the
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comprehensive molecular simulations demonstrated in this work constitute a novel toolbox to tackle this challenge.” The conclusion reported in this work is also applicable to explain the water solubilities of other polyethers, for example, dioxane versus trioxane. More generally, this work provides a new theory to predict the water solubilities of oxygen-containing polymers. Tianyu Liu
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roteins are organic biopolymers consisting of a sequence of smaller amino-acid units. However, unlike synthetic polymers, which are made from a single monomer repeated over and over, these amino acids come from a library of 20 different varieties, enabling proteins to fold into complex three-dimensional (3D) shapes that directly control their function. The research led by James J. De Yoreo and David Baker from the Pacific Northwest National Laboratory and the University of Washington, and published in a recent issue of Nature (doi:10.1038/ s41586-019-1361-6) focus on the selfassembly of proteins in the presence of crystals. Indeed, from ice-binding proteins to bone formation, there are indications showing that proteins and minerals can show strong binding affinity and play a role in the mineralization process. To study the binding of proteins to mineral surfaces, the team designed proteins that specifically bind to mica and self-assemble into ordered patterns on this surface. This binding is driven not only by electrostatics, but also via the specific 3D shapes that proteins adopt in liquid, to allow the carboxyl groups on the protein to match the crystal lattice. Therefore, to design the protein, they used a preexisting helical repeat protein (DHR) whose repeat unit is close to the spacing of the target mica lattice, namely 1.04 nm. The main hypothesis that the researchers validated is that for a protein to adsorb in a predictable orientation
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Atomic force microscope images showing the self-assembly of proteins on mica surfaces in presence of 3M KCl: highly packed 2D alignment of short protein rods (a), long nanowires (b), and hexagonal lattices (c). The inserts are zoom-in images and the fast Fourier transform of the hexagonal lattice, respectively. Credit: Nature.
onto the surface, the carboxylate groups of the protein should be spaced with the same distances as the atoms of the surface. First, the researchers used simulation tools to predict which protein sequence with the DHR repeat unit is required to achieve this specific binding. This sequence was then used to modify the DNA of a bacteria that was cultured to produce the artificially designed protein
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