School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Jingkou District, Zhenjiang 212013, Jiangsu, People's Republic of China.
School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Jingkou District, Zhenjiang 212013, Jiangsu, People's Republic of China.
Int J Biol Macromol. 2021 Apr 15;176:253-259. doi: 10.1016/j.ijbiomac.2021.02.081. Epub 2021 Feb 13.
Extracellular proteases from haloarchaea can expand the application fields of proteases. Exploring novel robust proteases is of great importance. An extracellular protease HlyA from Halococcus salifodinae was obtained by heterologous expression, affinity chromatography, in vitro refolding and gel filtration chromatography. Its activity was optimal at 45 °C, pH 9.0 and 1.5-2 M NaCl. Interestingly, although HlyA was from an extremely halophilic archaeon, it retained >75% of maximal activity in a broad NaCl concentration of 0.5-4 M. It displayed relatively stable activities over a wide range of temperature, pH and salinity. Thus, HlyA exhibited good temperature, pH and especially, salinity tolerance. Ca, Mg and Sr significantly enhanced the protease activity. HlyA activity was completely inhibited by phenylmethanesulfonyl fluoride (PMSF), suggesting it is a serine protease. HlyA showed good tolerance to some surfactants and organic solvents. The K and V values of HlyA for azocasein were calculated to be 0.72 mM and 21.98 U/μg, respectively. HlyA was able to effectively degrade several protein substrates, including bovine hemoglobin, casein and azocasein. Generally, HlyA from the extremely halophilic archaeon Hcc. salifodinae is an alkaliphilic and low salt-adapted halolysin with high activity, thus representing an attractive candidate for various industrial uses.
来自嗜盐古菌的细胞外蛋白酶可以扩展蛋白酶的应用领域。探索新型的、稳健的蛋白酶具有重要意义。本文通过异源表达、亲和层析、体外复性和凝胶过滤层析获得了来自盐杆菌属（Halococcus salifodinae）的细胞外蛋白酶 HlyA。其最适活性温度为 45°C，最适 pH 值为 9.0，最适盐浓度为 1.5-2 M NaCl。有趣的是，尽管 HlyA 来自极端嗜盐古菌，但它在 0.5-4 M 的广泛 NaCl 浓度下仍保留了超过 75%的最大活性。它在较宽的温度、pH 和盐度范围内表现出相对稳定的活性。因此，HlyA 表现出良好的温度、pH 值和耐盐性。Ca、Mg 和 Sr 显著增强了蛋白酶的活性。HlyA 的活性被苯甲基磺酰氟（PMSF）完全抑制，表明它是一种丝氨酸蛋白酶。HlyA 对一些表面活性剂和有机溶剂具有良好的耐受性。HlyA 对偶氮酪蛋白的 K 和 V 值分别为 0.72 mM 和 21.98 U/μg。HlyA 能够有效降解几种蛋白质底物，包括牛血红蛋白、酪蛋白和偶氮酪蛋白。总的来说，来自极端嗜盐古菌盐杆菌属（Hcc. salifodinae）的 HlyA 是一种具有高活性的嗜碱和低盐适应的嗜盐溶菌酶，因此是各种工业用途的有吸引力的候选酶。
