BACKGROUND Lignin, the second most abundant biopolymer on earth, plays a major structural role in plants, conferring mechanical strength and regulating water conduction. Understanding the three-dimensional structure of lignin is important for fundamental reasons as well as engineering plants towards lignin valorization. Lignin lacks a specific primary sequence, making its average chemical composition the focus of most recent studies. However, it remains unclear whether the 3D structure of lignin molecules depends on their sequence. METHODS We performed all-atom molecular dynamics simulation of three S/G-lignin molecules with the same average composition but different sequence. RESULTS A detailed statistical analysis of the radius of gyration and relative shape anisotropy reveals that the lignin sequence has no statistically significant effect on the global three-dimensional structure. We found however, that homopolymers of C-lignin with the same molecular weight have smaller radii of gyration than S/G-lignin. We attribute this to lower hydroxyl content of C-lignin, which makes it more compact and rigid. CONCLUSIONS The 3D structure of lignin is influenced by the overall content of monomeric units and interunit linkages and not by its precise primary sequence. GENERAL SIGNIFICANCE Lignin is assumed to not have a well-defined primary structure. The results presented here demonstrate there are no significant differences in the global 3D structure of lignin molecules with the same average composition but different primary sequence.

中文翻译：

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木质素序列与其3D结构之间的关系。

背景技术木质素是地球上第二丰富的生物聚合物，在植物中起主要结构作用，赋予机械强度并调节水的传导。出于根本原因，了解木质素的三维结构非常重要，这对于工程设计木质素的价值至关重要。木质素缺乏特定的一级序列，使其平均化学组成成为最新研究的重点。然而，尚不清楚木质素分子的3D结构是否取决于其序列。方法我们对三个具有相同平均组成但序列不同的S / G-木质素分子进行了全原子分子动力学模拟。结果对回转半径和相对形状各向异性的详细统计分析表明，木质素序列对整体三维结构没有统计学显着影响。但是，我们发现具有相同分子量的C-木质素均聚物的回转半径小于S / G-木质素。我们将其归因于C-木质素的较低羟基含量，这使其更致密，更坚硬。结论木质素的3D结构受单体单元和单元间连接的整体含量的影响，而不受其精确的主要序列的影响。一般意义假定木质素没有明确定义的一级结构。