Molecular Anatomy of Polysaccharide-degrading Enzymes from Extremophiles

极端微生物多糖降解酶的分子解剖学

• 批准号: 12650783
• 负责人: NAKAMURA Satoshi
• 金额: $ 2.24万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650783/
• 关键词: Biotechnology; Protein; Glycanase; Extremophile; Xylanase; Alkaliphilic Bacillus sp.; Catalytic domain; Xylan-binding domain; 触媒ドメイン; キシラン結合ドメイン; ファージディスプレイ; 進化分子工学; タンパク質工学; 反応至適pH

Many microorganisms have been discovered at unusual environments such as extreme temperature, pH and salinity. These microorganisms are called "extremophiles" that include thermophiles, psychrophiles, acidophiles, alkaliphiles and halophiles. "Extremozymes" are the enzymes produced by extremophiles and able to function under the extreme conditions. Extremozymes have tremendous potential for industrial applications as well as academic directions. Hemicellulose, originally named for the fraction extracted from plant cell walls with dilute alkali, is one of the most abundant polysaccharide in plant cell walls. Beta-1,4-Xylan is the major component of hemicelluloses ; it accounts for approximately 10 to 30% of the total dry weight of wood. Xylan is a heterogeneous polysaccharide comprising a backbone of beta-1,4- linked xylopyranose units with branches containing acetyl, L-arabino-furanosyl and glucopyranosyl residues. Xylanase (1,4-beta-D-xylan xylanohydrolase ; EC 3.2.1.8) catalyzes the hydrolysis of xylan to xylooligosaccharides and xylose. Alkaliphilic Bacillus sp. strain 41M-1 secretes a xylanase (xylanase J) that has an alkaline pH optimum. Xylanase J is a multidomain enzyme that consists of a family 11/G catalytic domain and a xylan-binding domain. Mutational analyzes revealed some amino acid residues that contribute to catalytic activity, alkaliphily and xylan-binding activity of xylanase J.

许多微生物是在极端温度、pH 值和盐度等异常环境中发现的。这些微生物被称为“极端微生物”，包括嗜热微生物、嗜冷微生物、嗜酸微生物、嗜碱微生物和嗜盐微生物。 “极端酶”是由极端微生物产生的酶，能够在极端条件下发挥作用。 Extremozymes 在工业应用和学术方向上具有巨大的潜力。半纤维素最初因用稀碱从植物细胞壁中提取的部分而得名，是植物细胞壁中含量最丰富的多糖之一。 Beta-1,4-Xylan是半纤维素的主要成分；它约占木材总干重的10%至30%。木聚糖是一种异质多糖，其包含β-1,4-连接的吡喃木糖单元的主链以及含有乙酰基、L-阿拉伯呋喃糖基和吡喃葡萄糖基残基的支链。木聚糖酶（1,4-β-D-木聚糖木聚糖水解酶；EC 3.2.1.8）催化木聚糖水解为低聚木糖和木糖。嗜碱芽孢杆菌属。菌株 41M-1 分泌具有碱性 pH 最适值的木聚糖酶（木聚糖酶 J）。木聚糖酶 J 是一种多结构域酶，由家族 11/G 催化结构域和木聚糖结合结构域组成。突变分析揭示了一些氨基酸残基有助于木聚糖酶 J 的催化活性、碱性和木聚糖结合活性。

项目成果

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