The biochemical basis behind the preferential presence and action of GmITPKs (myo-inositol—1, 3, 4 tris phosphate 5/6 kinases) in regulating the phosphorous flux towards phytate synthesis in soybean is an important, still unresolved question. In this study, context specific expression of GmITPKs in developing seeds was analysed, which found to be maximum at early stages (0–4 mm); while isozyme specificity was observed with varied dynamics till maturity. It is commonly believed that similarity at sequence level will infer similarity in structure as well, but the robust correlation between sequence and structure has not yet been proved. Hence full length coding sequences of GmITPKs were cloned and their sequence comparison revealed a low identity score of about 50% among the isoforms. Creative computational tools were employed to predict and comprehend the structural attributes and to explore the inverse correlation between the structural and sequence similarities of GmITPKs. Homology modeling of GmITPKs, their refinement and superposition validated the functional isoformic nature, with 92–97% similarity in spatial configuration. Ligand docking and energy computations showed ADP, IP₆ and IP₅ as possible ligands, and interactions were studied using docking and simulation. The homology models of GmITPKs were used as the starting point for nanosecond-duration molecular dynamics and were found to be stable during 20 ns simulation period. Existence of situation-specific functional basis for this isoform multiplicity, at structural and expression levels revealed to be a preferred regulatory mechanism to adapt to the metabolic fluctuations in inositol pathway during seed development.

中文翻译：

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Gm ITPK（肌醇：1、3、4三磷酸5/6激酶）同工型的功能表征-“如此不同却如此相似”

Gm ITPKs（肌醇-1、3、4三磷酸5/6激酶）优先存在和发挥作用的生物化学基础，在调节大豆通向植酸合成的磷通量方面，是一个重要但尚未解决的问题。在这项研究中，分析了发育中的种子中GmITPKs的背景特异性表达，发现其在早期阶段（0–4 mm）最高。同时观察到同工酶的特异性，并具有不同的动力学直至成熟。通常认为，在序列水平上的相似性也将推断结构上的相似性，但是尚未证明序列和结构之间的鲁棒相关性。因此，GmITPK的全长编码序列克隆了它们，它们的序列比较显示同工型之间的同一性评分较低，约为50％。创新的计算工具被用来预测和理解结构属性，并探索Gm ITPK的结构和序列相似性之间的逆相关性。Gm ITPK的同源性建模，其精细化和重叠验证了功能同构的性质，在空间配置上具有92–97％的相似性。配体对接和能量计算表明ADP，IP ₆和IP ₅是可能的配体，并且使用对接和模拟研究了相互作用。Gm的同源性模型ITPKs被用作纳秒持续时间分子动力学的起点，并且在20 ns仿真期间被发现是稳定的。在结构和表达水平上，这种同工型多重性存在因地制宜的功能基础，这是在种子发育过程中适应肌醇途径代谢波动的优选调控机制。