The repetitive sequence of glutenin plays an important role in dough rheology; however, its interaction with wheat protein disulfide isomerase (wPDI) remains unclear. In this study, the conformations of wild type glutenin repetitive sequence (WRS) from the high molecular weight glutenin subunit (HMW-GS) 1Dx5, an artificially designed glutenin repetitive sequence (DRS) of which the amino acid composition is the same but the primary structure is different, and wPDI under different redox states were simulated. The molecular interactions between the aforementioned repetitive sequences with wPDI under different redox states were further investigated. The results indicated that the repetitive sequences bind to the b and b′ domains of an “open”, oxidized wPDI (wPDIO) which serves as the acceptor state of substrate. The repetitive sequence is partially folded (compressed) in wPDIO, and is further folded in the thermodynamically favored, subsequent conformational transition of wPDIO to reduced wPDI (wPDIR). Compared with the artificially designed one, the naturally designed repetitive sequence is better recognized and more intensively folded by wPDI for its later unfold as the molecular basis of dough extension.

中文翻译：

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wPDI氧化还原循环耦合HMW-GS 1Dx5重复域的构象变化——一项计算研究

谷蛋白的重复序列在面团流变学中起着重要作用；然而，它与小麦蛋白二硫键异构酶（wPDI）的相互作用仍不清楚。在这项研究中，来自高分子量谷蛋白亚基 (HMW-GS) 1Dx5 的野生型谷蛋白重复序列​​ (WRS) 的构象，这是一种人工设计的谷蛋白重复序列​​ (DRS)，其氨基酸组成相同但主要结构不同，模拟了不同氧化还原状态下的wPDI。进一步研究了在不同氧化还原状态下上述重复序列与 wPDI 之间的分子相互作用。结果表明，重复序列与作为底物受体状态的“开放”氧化 wPDI (wPDIO) 的 b 和 b' 结构域结合。重复序列在 wPDIO 中部分折叠（压缩），并在 wPDIO 到减少的 wPDI (wPDIR) 的热力学有利的后续构象转变中进一步折叠。与人工设计的重复序列相比，自然设计的重复序列被 wPDI 更好地识别和更密集地折叠，以便稍后展开，作为面团拉伸的分子基础。