Rakhra Gurmeen, Kaur Tarandeep, Vyas Dhiraj, Sharma Arun Dev, Singh Jatinder, Ram Gobind
PG Department of Biotechnology, Lyallpur Khalsa College, G.T. Road, Jalandhar 144001, Punjab, India.
Biodiversity and Applied Botany Division, Indian Institute of Integrative Medicine (CSIR), Canal Road, Jammu 180001, India.
Plant Physiol Biochem. 2017 Mar;112:29-44. doi: 10.1016/j.plaphy.2016.12.017. Epub 2016 Dec 23.
The structural and physico-chemical properties that account for the multi-functionality of dehydrins remain largely unknown. In this study, we identified, sequenced and cloned a stress regulated cDNA encoding a dehydrin-like boiling stable protein (designated as wBsSRP; wheat boiling stable stress responsive protein) from drought stressed seedlings of drought tolerant cultivar of wheat (PBW 175). qRT-PCR analysis documented high transcripts levels of wBsSRP during drought and cold conditions in the tolerant cv. PBW 175 as a part of adaptive response to stress while the levels were significantly lower in the sensitive cv. PBW 343. We also describe in-silico characterization and molecular modeling of wBsSRP through homology search, motif analysis, secondary structure prediction, active site prediction and 3D structure analysis. The physico-chemical properties and theoretical data of wBsSRP depicts that it is a canonical group 2 LEA protein. The recombinant wBsSRP protein when expressed in E. coli detected a specific differential band (∼11 kDa) on SDS- PAGE after IPTG induction. The functional analysis of wBsSRP in E. coli revealed that wBsSRP is essential for the survival of E. coli as well as for maintaining bacterial growth under various stress conditions. In vitro peroxidase protection assay during heat stress (50 and 100 °C) showed that in the presence of wBsSRP, peroxidase activity was significantly retained and/or increased. Based upon the findings, it is suggested that wBsSRP accentuated the effects of stress by acting as a protectant and by the stabilization of membranes, thereby contributing to the improved stress tolerance of the recombinant E. coli under various abiotic stress conditions. We suggest that these findings might provide the rationale for the mechanism of how these proteins obviate the adverse effects of dehydration stress.
脱水素多功能性的结构和物理化学性质在很大程度上仍然未知。在本研究中,我们从耐旱小麦品种(PBW 175)的干旱胁迫幼苗中鉴定、测序并克隆了一个受胁迫调控的cDNA,其编码一种类似脱水素的热稳定蛋白(命名为wBsSRP;小麦热稳定胁迫响应蛋白)。qRT-PCR分析表明,在耐旱品种PBW 175中,干旱和寒冷条件下wBsSRP的转录水平很高,这是对胁迫的适应性反应的一部分,而在敏感品种PBW 343中,其水平显著较低。我们还通过同源性搜索、基序分析、二级结构预测、活性位点预测和三维结构分析,对wBsSRP进行了电子克隆表征和分子建模。wBsSRP的物理化学性质和理论数据表明它是一种典型的2组LEA蛋白。在IPTG诱导后,重组wBsSRP蛋白在大肠杆菌中表达时,在SDS-PAGE上检测到一条特异性差异条带(约11 kDa)。wBsSRP在大肠杆菌中的功能分析表明,wBsSRP对于大肠杆菌的存活以及在各种胁迫条件下维持细菌生长至关重要。热胁迫(50和100℃)期间的体外过氧化物酶保护试验表明,在wBsSRP存在的情况下,过氧化物酶活性显著保留和/或增加。基于这些发现,表明wBsSRP通过作为保护剂和稳定膜来增强胁迫效应,从而有助于重组大肠杆菌在各种非生物胁迫条件下提高胁迫耐受性。我们认为,这些发现可能为这些蛋白质消除脱水胁迫不利影响的机制提供理论依据。