Abstract The Resistant (R) proteins play a fundamental role in the innate immunity of plants. Most of these R-proteins have centrally located NB-ARC domain which regulates the R-protein by NTPase activity. Though the effect of amino acid substitution in RNBS, MHD motifs of the NB-ARC domain has been studied in detail, the P-loop motif remains still less explored. With the help of in-silico analysis of a hypothetical R-protein (Hyp-R) in sesame, we tested the hypothesis that how amino acid substitution in the conserved P-loop motif can affect the interaction between ligand and NB-ARC domain. We report I188G, I188V, T192P substitution in P-loop motif and V356S adjacent to GLPL motif in three different sesame genotypes. Docking results and atomic interaction analysis revealed a cumulative effect of these substitutions on the hydrogen bond interactions, which in turn impart effects on ligand binding affinity in Sesamum indicum (-6.6 kcal/mol), Sesamum mulayanum (-7.3 kcal/mol) and recombinant line (-7.5 kcal/mol). We correlated expression of the R-gene encoding Hyp-R protein in sesame after inoculating with Macrophomina phaseolina. This study suggests that amino acid substitution in P-loop and adjacent to GLPL motif have an immense effect on ligand binding affinity.

中文翻译：

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芝麻中假设 R 蛋白保守基序中的氨基酸取代对 ADP 结合位置和氢键相互作用产生显着影响

摘要 抗性 (R) 蛋白在植物的先天免疫中起重要作用。大多数这些 R 蛋白具有位于中央的 NB-ARC 结构域，其通过 NTPase 活性调节 R 蛋白。尽管已经详细研究了 RNBS 中氨基酸取代的影响，NB-ARC 域的 MHD 基序，但 P-loop 基序仍然很少被探索。在对芝麻中假设的 R 蛋白 (Hyp-R) 进行计算机分析的帮助下，我们测试了保守 P 环基序中的氨基酸取代如何影响配体和 NB-ARC 结构域之间的相互作用的假设。我们报告了三种不同芝麻基因型中 P 环基序中的 I188G、I188V、T192P 替换和与 GLPL 基序相邻的 V356S。对接结果和原子相互作用分析揭示了这些取代对氢键相互作用的累积影响，这反过来又对芝麻 (-6.6 kcal/mol)、芝麻 (-7.3 kcal/mol) 和重组体中的配体结合亲和力产生影响线 (-7.5 kcal/mol)。我们将芝麻中编码 Hyp-R 蛋白的 R 基因的表达相关联。该研究表明，P 环中和 GLPL 基序附近的氨基酸取代对配体结合亲和力有巨大影响。