WPI Nano Life Science Institute, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
Institute for Frontier Science and Initiative, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
ACS Nano. 2023 Apr 25;17(8):7311-7325. doi: 10.1021/acsnano.2c10673. Epub 2023 Mar 1.
Understanding the mechanisms of self-organization of short peptides into two- and three-dimensional architectures are of great interest in the formation of crystalline biomolecular systems and their practical applications. Since the assembly is a dynamic process, the study of structural development is challenging at the submolecular dimensions continuously across an adequate time scale in the natural biological environment, in addition to the complexities stemming from the labile molecular structures of short peptides. Self-organization of solid binding peptides on surfaces offers prospects to overcome these challenges. Here we use a graphite binding dodecapeptide, GrBP5, and record its self-organization process of the first two layers on highly oriented pyrolytic graphite surface in an aqueous solution by using frequency modulation atomic force microscopy . The observations suggest that the first layer forms homogeneously, generating self-organized crystals with a lattice structure in contact with the underlying graphite. The second layer formation is mostly heterogeneous, triggered by the crystalline defects on the first layer, growing row-by-row establishing nominally diverse biomolecular self-organized structures with transient crystalline phases. The assembly is highly dependent on the peptide concentration, with the nucleation being high in high molecular concentrations, e.g., >100 μM, while the domain size is small, with an increase in the growth rate that gradually slows down. Self-assembled peptide crystals are composed of either singlets or doublets establishing and oblique lattices, respectively, each commensurate with the underlying graphite lattice with chiral crystal relations. This work provides insights into the surface behavior of short peptides on solids and offers quantitative guidance toward elucidating molecular mechanisms of self-assembly helping in the scientific understanding and construction of coherent bio/nano hybrid interfaces.
理解短肽自组装成二维和三维结构的机制对于晶态生物分子体系的形成及其实际应用具有重要意义。由于组装是一个动态过程，因此在自然生物环境中，在足够的时间尺度内，从亚分子维度研究结构的发展具有挑战性，此外，还存在短肽分子结构不稳定带来的复杂性。在表面上将固体结合肽自组装提供了克服这些挑战的前景。在这里，我们使用石墨结合十二肽 GrBP5，并通过调频原子力显微镜记录其在水溶液中在高度取向的热解石墨表面上的前两层的自组织过程。观察结果表明，第一层均匀形成，与底层石墨接触生成具有晶格结构的自组织晶体。第二层的形成主要是非均匀的，由第一层的晶体缺陷触发，逐行生长，建立具有瞬态晶体相的名义上不同的生物分子自组织结构。组装高度依赖于肽浓度，在高分子浓度下（例如 >100 μM），成核较高，而畴尺寸较小，随着生长速率的增加逐渐减慢。自组装的肽晶体由单分子或双分子组成，分别建立和斜晶格，每个晶格与底层石墨晶格具有手性晶体关系相一致。这项工作深入了解了短肽在固体表面上的行为，并为阐明自组装的分子机制提供了定量指导，有助于科学理解和构建连贯的生物/纳米杂化界面。
