Alginate-modifying enzymes: biological roles and biotechnological uses.
Alginate-modifying enzymes: biological roles and biotechnological uses.
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DOI：
10.3389/fmicb.2015.00523
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发表时间：
2015
影响因子：
5.2
通讯作者：
Ertesvåg H
中科院分区：
文献类型：
--
作者：
Ertesvåg H
海藻酸盐是指一组工业上重要的 1-4 连接生物聚合物，由 C-5-差向异构体 β-D-甘露糖醛酸 (M) 和 α-L-古洛糖醛酸 (G) 组成。多糖由褐藻制成，构成细胞壁的主要结构聚合物。给定藻酸盐分子的物理性质，例如凝胶强度、水结合能力、粘度和生物相容性，由聚合物长度、G残基的相对量和分布以及乙酰基含量决定，所有这些都由藻酸盐修饰酶控制。藻酸盐也已从属于假单胞菌属和固氮杆菌属的一些细菌中分离出来，并且细菌合成的藻酸盐可能在O-2和/或O-3处被O-乙酰化。最初，藻酸盐被合成为聚甘露糖醛酸，一些M残基随后差向异构化为G残基。在细菌中，甘露糖醛 C-5-差向异构酶 (AlgG) 和藻酸盐乙酰化酶 (AlgX) 是藻酸盐聚合和输出所必需的蛋白质复合物的组成部分。所有产生藻酸盐的细菌都使用周质藻酸盐裂合酶来去除异常释放到周质的藻酸盐分子。藻酸盐裂解酶也由利用藻酸盐作为碳源的生物体产生。大多数藻酸盐生产生物体编码不止一种甘露糖醛 C-5 差向异构酶，每种都引入其特定的 G 残基模式。乙酰化可防止进一步差向异构化和大多数藻酸盐裂解酶。据报道，来自丁香假单胞菌的一种酶具有藻酸盐脱乙酰酶活性。功能和结构研究表明，藻酸盐裂解酶和差向异构酶具有相关的酶机制和催化位点。海藻酸盐裂解酶现在被用作藻酸盐表征的工具。分泌性差向异构酶已被证明在体外具有良好的功能，并且已被进一步改造以获得可以为藻酸盐提供新的和所需特性的酶，用于医疗和制药应用。
Alginate denotes a group of industrially important 1-4-linked biopolymers composed of the C-5-epimers β-D-mannuronic acid (M) and α-L-guluronic acid (G). The polysaccharide is manufactured from brown algae where it constitutes the main structural cell wall polymer. The physical properties of a given alginate molecule, e.g., gel-strength, water-binding capacity, viscosity and biocompatibility, are determined by polymer length, the relative amount and distribution of G residues and the acetyl content, all of which are controlled by alginate modifying enzymes. Alginate has also been isolated from some bacteria belonging to the genera Pseudomonas and Azotobacter, and bacterially synthesized alginate may be O-acetylated at O-2 and/or O-3. Initially, alginate is synthesized as polymannuronic acid, and some M residues are subsequently epimerized to G residues. In bacteria a mannuronan C-5-epimerase (AlgG) and an alginate acetylase (AlgX) are integral parts of the protein complex necessary for alginate polymerization and export. All alginate-producing bacteria use periplasmic alginate lyases to remove alginate molecules aberrantly released to the periplasm. Alginate lyases are also produced by organisms that utilize alginate as carbon source. Most alginate-producing organisms encode more than one mannuronan C-5 epimerase, each introducing its specific pattern of G residues. Acetylation protects against further epimerization and from most alginate lyases. An enzyme from Pseudomonas syringae with alginate deacetylase activity has been reported. Functional and structural studies reveal that alginate lyases and epimerases have related enzyme mechanisms and catalytic sites. Alginate lyases are now utilized as tools for alginate characterization. Secreted epimerases have been shown to function well in vitro, and have been engineered further in order to obtain enzymes that can provide alginates with new and desired properties for use in medical and pharmaceutical applications.
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DOI：
10.1139/v66-147
发表时间：
1966-01-01
期刊：
CANADIAN JOURNAL OF CHEMISTRY-BACK YEAR
影响因子：
--
作者：
GORIN, PAJ;SPENCER, JFT
通讯作者：
SPENCER, JFT
影响因子：
6.8
作者：
Garron, Marie-Line;Cygler, Miroslaw
通讯作者：
Cygler, Miroslaw
影响因子：
4.8
作者：
Buchinger, Edith;Knudsen, Daniel H.;Aachmann, Finn L.
通讯作者：
Aachmann, Finn L.
影响因子：
11.4
作者：
BAUMANN, U;WU, S;MCKAY, DB
通讯作者：
MCKAY, DB
影响因子：
3.2
作者：
Franklin, MJ;Ohman, DE
通讯作者：
Ohman, DE