Data_Sheet_1_XynDZ5: A New Thermostable GH10 Xylanase.pdf

Xylanolytic enzymes have a broad range of applications in industrial biotechnology as biocatalytic components of various processes and products, such as food additives, bakery products, coffee extraction, agricultural silage and functional foods. An increasing market demand has driven the growing interest for the discovery of xylanases with specific industrially relevant characteristics, such as stability at elevated temperatures and in the presence of other denaturing factors, which will facilitate their incorporation into industrial processes. In this work, we report the discovery and biochemical characterization of a new thermostable GH10 xylanase, termed XynDZ5, exhibiting only 26% amino acid sequence identity to the closest characterized xylanolytic enzyme. This new enzyme was discovered in an Icelandic hot spring enrichment culture of a Thermoanaerobacterium species using a recently developed bioinformatic analysis platform. XynDZ5 was produced recombinantly in Escherichia coli, purified and characterized biochemically. This analysis revealed that it acts as an endo-1,4-β-xylanase that performs optimally at 65–75°C and pH 7.5. The enzyme is capable of retaining high levels of catalytic efficiency after several hours of incubation at high temperatures, as well as in the presence of significant concentrations of a range of metal ions and denaturing agents. Interestingly, the XynDZ5 biochemical profile was found to be atypical, as it also exhibits significant exo-activity. Computational modeling of its three-dimensional structure predicted a (β/α)8 TIM barrel fold, which is very frequently encountered among family GH10 enzymes. This modeled structure has provided clues about structural features that may explain aspects of its catalytic performance. Our results suggest that XynDZ5 represents a promising new candidate biocatalyst appropriate for several high-temperature biotechnological applications in the pulp, paper, baking, animal-feed and biofuel industries.

木聚糖酶在工业生物技术领域具有广泛的应用，作为各类工艺和产品的生物催化成分，例如食品添加剂、烘焙产品、咖啡提取、农业青贮和功能性食品。随着市场需求日益增长，对具有特定工业相关特性的木聚糖酶的发现兴趣亦日益浓厚，例如在高温和存在其他变性因素下的稳定性，这将有助于其融入工业生产过程。在本研究中，我们报道了一种新型耐热GH10木聚糖酶XynDZ5的发现及其生化特性鉴定，该酶与最近的鉴定木聚糖酶的氨基酸序列同源性仅为26%。此新酶是通过一种最近开发的生物信息学分析平台，在冰岛温泉富集培养Thermoanaerobacterium物种时发现的。XynDZ5在大肠杆菌中进行了重组生产，经纯化后进行了生化特性鉴定。分析表明，该酶作为一种内切-1,4-β-木聚糖酶，在65-75°C和pH 7.5的条件下表现出最佳活性。该酶在高温孵育数小时后以及存在大量金属离子和变性剂的情况下，仍能保持高水平的催化效率。有趣的是，XynDZ5的生化特征被发现较为独特，因为它还表现出显著的端外活性。对其三维结构的计算建模预测了一个(β/α)8 TIM桶状折叠，这在GH10家族酶中非常常见。该模型结构为解释其催化性能的结构特征提供了线索。我们的研究结果表明，XynDZ5是一种具有潜力的新型生物催化剂，适用于纸浆、造纸、烘焙、动物饲料和生物燃料等行业中的多种高温生物技术应用。