Faculty of Agriculture, Meijo University, Nagoya, Aichi, 468-0073, Japan.
Appl Biochem Biotechnol. 2022 Dec;194(12):5627-5643. doi: 10.1007/s12010-022-04036-x. Epub 2022 Jul 8.
Pectinolytic enzymes have diverse industrial applications. Among these, pectate lyases act on the internal α-1,4-linkage of the pectate backbone, playing a critical role in pectin degradation. While most pectate lyases characterized thus far are of bacterial origin, fungi can also be excellent sources of pectinolytic enzymes. In this study, we performed biochemical characterization of the pectate lyase AnPL9 belonging to the polysaccharide lyase family 9 (PL9) from the filamentous fungus Aspergillus nidulans. Recombinant AnPL9 was produced using a Pichia pastoris expression system and purified. AnPL9 exhibited high activity on homogalacturonan (HG), pectin from citrus peel, pectin from apple, and the HG region in rhamnogalacturonan-I. Although digalacturonic acid and trigalacturonic acid were not degraded by AnPL9, tetragalacturonic acid was converted to 4,5-unsaturated digalacturonic acid and digalacturonic acid. These results indicate that AnPL9 degrades HG oligosaccharides with a degree of polymerization > 4. Furthermore, AnPL9 was stable within a neutral-to-alkaline pH range (pH 6.0-11.0). Our findings suggest that AnPL9 is a candidate pectate lyase for biotechnological applications in the food, paper, and textile industries. This is the first report on a fungal pectate lyase belonging to the PL9 family.
果胶裂解酶具有多种工业应用。其中，果胶酸裂解酶作用于果胶主链的内部α-1,4-键，在果胶降解中起着关键作用。虽然迄今为止大多数鉴定的果胶酸裂解酶都来自细菌，但真菌也可以是果胶裂解酶的极好来源。在这项研究中，我们对丝状真菌 Aspergillus nidulans 中的多糖裂解酶家族 9 (PL9) 的果胶酸裂解酶 AnPL9 进行了生化特性分析。使用巴斯德毕赤酵母表达系统生产和纯化重组 AnPL9。AnPL9 在同半乳糖醛酸聚糖 (HG)、柑橘皮果胶、苹果果胶和鼠李半乳糖醛酸聚糖 I 的 HG 区域表现出高活性。尽管二半乳糖醛酸和三半乳糖醛酸不能被 AnPL9 降解，但四半乳糖醛酸转化为 4,5-不饱和二半乳糖醛酸和二半乳糖醛酸。这些结果表明 AnPL9 可降解聚合度>4 的 HG 寡糖。此外，AnPL9 在中性至碱性 pH 范围内（pH 6.0-11.0）稳定。我们的研究结果表明，AnPL9 是食品、造纸和纺织工业中生物技术应用的候选果胶酸裂解酶。这是关于属于 PL9 家族的真菌果胶酸裂解酶的首次报道。
