a Department of Biotechnology, School of Bioscience and Technology , VIT University , Vellore 632014 , India.
J Biomol Struct Dyn. 2019 Feb;37(3):750-765. doi: 10.1080/07391102.2018.1439770. Epub 2018 Feb 20.
Singleton-Merten syndrome, a critical and rare multifactorial disorder that is closely linked to R516Q mutation in MDA5 protein associated with an enhanced interferon response in the affected individual. In the present study, we provide conclusive key evidence on R516Q mutation and their connectivity towards sequence-structural basis dysfunction of MDA5 protein. Among the various mutations, we found R516Q is the most pathogenic mutation based on mutational signature Q-A-[RE]-G-R-[GA]-R-A-[ED]-[DE]-S-[ST]-Y-[TSAV]-L-V designed from our work. Further, we derived a distant ortholog for this mutational signature from which we identified 343 intra-residue interactions that fall communally in the position required to maintain the structural and functional integration of protein architecture. This identification served us to understand the critical role of hot spots in residual aggregation that holds a native form of folding conformation in the functional region. In addition, the long-range molecular dynamics simulation demarcated the residual dependencies of conformational transition in distinct regions (360-370, 380-410, 430-480 and 510-520) occurring upon R516Q mutation. Together, our results emphasise that the dislocation of functional hot spots Pro229, Arg414, Val498, Met510, Ala513, Gly515 and Arg516 in MDA5 protein which is important for interior structural packing and fold arrangements. In a nutshell, our findings are perfectly conceded with other experimental reports and will have potential implications in immune therapeutical advancement for rare singleton-merten syndrome.
Singleton-Merten 综合征是一种严重且罕见的多因素疾病,与 MDA5 蛋白中的 R516Q 突变密切相关,该突变会导致受影响个体的干扰素反应增强。在本研究中,我们提供了关于 R516Q 突变及其与 MDA5 蛋白序列-结构基础功能障碍相关性的确凿关键证据。在各种突变中,我们发现 R516Q 是最具致病性的突变,这是基于我们的工作设计的突变特征 Q-A-[RE]-G-R-[GA]-R-A-[ED]-[DE]-S-[ST]-Y-[TSAV]-L-V。此外,我们从该突变特征中推导出了一个遥远的直系同源物,从中我们确定了 343 个残基内相互作用,这些相互作用共同位于维持蛋白质结构和功能整合所需的位置。这种鉴定使我们能够理解残基聚集中的热点在保持功能区域中天然折叠构象方面的关键作用。此外,长程分子动力学模拟标记了在 R516Q 突变时发生的不同区域(360-370、380-410、430-480 和 510-520)构象转变的剩余依赖性。总之,我们的结果强调了 MDA5 蛋白中功能热点(Pro229、Arg414、Val498、Met510、Ala513、Gly515 和 Arg516)的位置错位,这些热点对于内部结构包装和折叠排列很重要。简而言之,我们的发现与其他实验报告完全一致,并将对罕见的Singleton-Merten 综合征的免疫治疗进展具有潜在意义。