Sinelnikov Igor G, Siedhoff Niklas E, Chulkin Andrey M, Zorov Ivan N, Schwaneberg Ulrich, Davari Mehdi D, Sinitsyna Olga A, Shcherbakova Larisa A, Sinitsyn Arkady P, Rozhkova Aleksandra M
Federal Research Centre Fundamentals of Biotechnology, Russian Academy of Sciences, Moscow, Russia.
Institute of Biotechnology, RWTH Aachen University, Aachen, Germany.
Front Bioeng Biotechnol. 2021 Sep 21;9:728501. doi: 10.3389/fbioe.2021.728501. eCollection 2021.
Recently, the study of chitinases has become an important target of numerous research projects due to their potential for applications, such as biocontrol pest agents. Plant chitinases from carnivorous plants of the genus are most aggressive against a wide range of phytopathogens. However, low solubility or insolubility of the target protein hampered application of chitinases as biofungicides. To obtain plant chitinase from carnivorous plants of the genus in soluble form in expression strains, three different approaches including dialysis, rapid dilution, and refolding on Ni-NTA agarose to renaturation were tested. The developed « Rapid dilution » protocol with renaturation buffer supplemented by 10% glycerol and 2M arginine in combination with the redox pair of reduced/oxidized glutathione, increased the yield of active soluble protein to 9.5 mg per 1 g of wet biomass. A structure-based removal of free cysteines in the core domain based on homology modeling of the structure was carried out in order to improve the soluble of chitinase. One improved chitinase variant (C191A/C231S/C286T) was identified which shows improved expression and solubility in expression systems compared to wild type. Computational analyzes of the wild-type and the improved variant revealed overall higher fluctuations of the structure while maintaining a global protein stability. It was shown that free cysteines on the surface of the protein globule which are not involved in the formation of inner disulfide bonds contribute to the insolubility of chitinase from . The functional characteristics showed that chitinase exhibits high activity against colloidal chitin (360 units/g) and high fungicidal properties of recombinant chitinases against Latter highlights the application of chitinase from as a promising enzyme for the control of fungal pathogens in agriculture.
最近,由于几丁质酶在诸如生物防治害虫制剂等方面的应用潜力,对其的研究已成为众多研究项目的重要目标。狸藻属食虫植物中的植物几丁质酶对多种植物病原体具有最强的活性。然而,目标蛋白的低溶解性或不溶性阻碍了几丁质酶作为生物杀菌剂的应用。为了在大肠杆菌表达菌株中获得可溶性形式的狸藻属食虫植物的植物几丁质酶,测试了三种不同的方法,包括透析、快速稀释以及在Ni-NTA琼脂糖上复性以实现重折叠。所开发的“快速稀释”方案,其复性缓冲液中添加了10%甘油和2M精氨酸,并结合还原型/氧化型谷胱甘肽氧化还原对,使活性可溶性蛋白的产量提高到每1克湿生物质9.5毫克。基于结构的同源建模对核心结构域中的游离半胱氨酸进行去除,以提高几丁质酶的可溶性。鉴定出一种改进的几丁质酶变体(C191A/C231S/C286T),与野生型相比,它在大肠杆菌表达系统中表现出更好的表达和溶解性。对野生型和改进变体的计算分析表明,在保持整体蛋白质稳定性的同时,结构的整体波动更大。结果表明,蛋白质球表面未参与内部二硫键形成的游离半胱氨酸导致了狸藻几丁质酶的不溶性。功能特性表明,几丁质酶对胶体几丁质具有高活性(360单位/克),重组几丁质酶对灰葡萄孢具有高杀菌特性。后者突出了狸藻几丁质酶作为一种有前途的酶在农业中控制真菌病原体的应用。