Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
Laboratory for Atomistic and Molecular Mechanics, Massachusetts Institute of Technology, 33 Massachusetts Avenue, Cambridge, MA 02139, USA.
Soft Matter. 2023 May 31;19(21):3917-3924. doi: 10.1039/d3sm00360d.
Several biological organisms utilize metal-coordination bonds to produce remarkable materials, such as the jaw of the marine worm , where metal-coordination bonds yield remarkable hardness without mineralization. Though the structure of a major component of the jaw, the Nvjp-1 protein, has recently been resolved, a detailed nanostructural understanding of the role of metal ions on the structural and mechanical properties of the protein is missing, especially with respect to the localization of metal ions. In this work, atomistic replica exchange molecular dynamics with explicit water and Zn ions and steered molecular dynamics simulations were used to explore how the initial localization of the Zn ions impacts the structural folding and mechanical properties of Nvjp-1. We found that the initial distribution of metal ions for Nvjp-1, and likely for other proteins with high amounts of metal-coordination, has important effects on the resulting structure, with larger metal ion quantity resulting in a more compact structure. These structural compactness trends, however, are independent from the mechanical tensile strength of the protein, which increases with greater hydrogen bond content and uniform distribution of metal ions. Our results indicate that different physical principles underlie the structure or mechanics of Nvjp-1, with broader implications in the development optimized hardened bioinspired materials and the modeling of proteins with significant metal ion content.
几种生物利用金属配位键来产生显著的材料，例如海洋蠕虫的下颚，其中金属配位键在没有矿化的情况下产生显著的硬度。尽管下颚的主要成分之一 Nvjp-1 蛋白的结构最近已经解析，但对于金属离子对该蛋白结构和机械性能的详细纳米结构理解仍存在缺失，特别是对于金属离子的定位。在这项工作中，使用原子置换分子动力学模拟与明确的水和 Zn 离子以及导向分子动力学模拟来探索 Zn 离子的初始定位如何影响 Nvjp-1 的结构折叠和机械性能。我们发现，Nvjp-1 中金属离子的初始分布，以及可能对于其他具有大量金属配位的蛋白质，对最终结构具有重要影响，金属离子数量越大，结构越紧凑。然而，这些结构紧凑度趋势与蛋白质的机械拉伸强度无关，拉伸强度随着氢键含量和金属离子分布的均匀性的增加而增加。我们的结果表明，Nvjp-1 的结构或力学性质由不同的物理原理决定，这对开发优化的硬化仿生材料和具有显著金属离子含量的蛋白质建模具有广泛的意义。
