Enabling Chemoenzymatic Strategies and Enzymes for Synthesizing Sialyl Glycans and Sialyl Glycoconjugates.
Enabling Chemoenzymatic Strategies and Enzymes for Synthesizing Sialyl Glycans and Sialyl Glycoconjugates.
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实现合成唾液酸聚糖和唾液酸糖偶联物的化学酶策略和酶。
DOI：
10.1021/acs.accounts.3c00614
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发表时间：
2024-01-16
影响因子：
18.3
通讯作者：
Chen, Xi
中科院分区：
文献类型：
--
作者：
Chen, Xi
唾液酸是一种迷人的带负电荷的九碳单糖。含唾液酸的葡聚糖和糖共轭化合物是结构多样、功能重要和具有合成挑战性的分子。我们开发了高效的化学酶策略，结合了化学合成和酶催化的力量，使唾液酸、唾液酸聚糖、唾液酸糖结合物及其衍生物更容易获得，使我们能够努力探索它们的功能和应用。报告首先简要描述了天然唾液酸和唾液酸苷的结构多样性和功能重要性。然后介绍了一锅多酶(OPME)化学酶促唾液酸化策略的发展，重点介绍了OPME在唾液酸转移酶供体底物工程策略合成结构多样化唾液酸苷方面的优势。有了该战略，现在可以系统地获得含有不同唾液酸形式的唾液酸苷，并在C3/4/5/7/8/9处进行修饰，获得各种内部多糖和不同的唾液酸键。还简要描述了将OPME唾液酸化策略与细菌唾液酸酶相结合来合成唾液酸酶抑制剂。为了简化酶促糖基化反应的产物纯化过程，含有天然疏水标签的鞘糖脂是化学酶全合成的理想靶标。开发了一种简单、高效的化学酶促反应策略，该策略包括三个主要过程，包括化学合成作为含TAG的水溶性中间体的乳糖基鞘氨醇，OPME用单一的C18-色谱柱对其多聚糖组分进行延伸，纯化产物，然后进行简单的化学酰化反应。该策略允许在产品中引入不同形式的唾液酸和不同的脂肪酰链。已经演示了克级合成。OPME唾液酸化也被证明用于化学酶法合成唾液酸糖肽，以及在体外酶促N-糖链与双唾液酸化的双天线复合型N-糖链形成糖蛋白。为了合成人乳寡糖(HMOS)，它是一种具有自由还原末端的多糖，开发了受体底物工程和工艺工程策略，其中包括设计一种疏水标签，该标签可以很容易地安装到受体底物中，以便从酶反应中轻松地提纯产物，并且可以在最后一步方便地去除以产生目标分子。该过程工程包括在多步骤OPME反应的中间步骤中对酶进行热灭活，以便在单一反应锅中和使用单一C18柱纯化过程中生产长链唾液酸苷靶标。此外，还开发了一种化学酶合子策略。它包括设计唾液酸基转移酶供体底物前体的衍生物，它在OPME反应中被酶所容忍，引入到酶产物中，然后在最后一步化学转化为所需的目标结构。化学酶合成子方法与受体底物工程方法相结合，用于合成含唾液酸、军团氨基酸及其衍生物的复合菌多糖。描述了由Chen小组开发的生物催化剂的特征及其工程突变体，重点介绍了合成有用的酶。我们期待着化学酶策略和生物催化剂的进一步发展，以使探索唾液酸空间成为可能。
Sialic acids are fascinating negatively charged nine-carbon monosaccharides. Sialic acid-containing glycans and glycoconjugates are structurally diverse, functionally important, and synthetically challenging molecules. We have developed highly efficient chemoenzymatic strategies that combine the power of chemical synthesis and enzyme catalysis to make sialic acids, sialyl glycans, sialyl glycoconjugates, and their derivatives more accessible, enabling the efforts to explore their functions and applications. The Account starts with a brief description of the structural diversity and the functional importance of naturally occurring sialic acids and sialosides. The development of one-pot multienzyme (OPME) chemoenzymatic sialylation strategies is then introduced, highlighting its advantages in synthesizing structurally diverse sialosides with a sialyltransferase donor substrate engineering tactic. With the strategy, systematic access to sialosides containing different sialic acid forms with modifications at C3/4/5/7/8/9, various internal glycans, and diverse sialyl linkages is now possible. Also briefly described is the combination of the OPME sialylation strategy with bacterial sialidases for synthesizing sialidase inhibitors. With the goal of simplifying the product purification process for enzymatic glycosylation reactions, glycosphingolipids that contain a naturally existing hydrophobic tag are attractive targets for chemoenzymatic total synthesis. A user-friendly highly efficient chemoenzymatic strategy is developed which involves three main processes, including chemical synthesis of lactosyl sphingosine as a water-soluble hydrophobic tag-containing intermediate, OPME enzymatic extension of its glycan component with a single C18-cartridge purification of the product, followed by a facile chemical acylation reaction. The strategy allows the introduction of different sialic acid forms and diverse fatty acyl chains into the products. Gram-scale synthesis has been demonstrated. OPME sialylation has also been demonstrated for the chemoenzymatic synthesis of sialyl glycopeptides and in vitro enzymatic N-glycan processing for the formation of glycoproteins with disialylated biantennary complex-type N-glycans. For synthesizing human milk oligosaccharides (HMOs) which are glycans with a free reducing end, acceptor substrate engineering and process engineering strategies are developed, which involve the design of a hydrophobic tag that can be easily installed into the acceptor substrate to allow facile purification of the product from enzymatic reactions and can be conveniently removed in the final step to produce target molecules. The process engineering involves heat-inactivation of enzymes in the intermediate steps in multistep OPME reactions for the production of long-chain sialoside targets in a single reaction pot and with a single C18-cartridge purification process. In addition, a chemoenzymatic synthon strategy has been developed. It involves the design of a derivative of the sialyltransferase donor substrate precursor, which is tolerated by enzymes in OPME reactions, introduced to enzymatic products, and then chemically converted to the desired target structures in the final step. The chemoenzymatic synthon approach has been used together with the acceptor substrate engineering method in the synthesis of complex bacterial glycans containing sialic acids, legionaminic acids, and derivatives. The biocatalysts characterized and their engineered mutants developed by the Chen group are described, with highlights on synthetically useful enzymes. We anticipate further development of chemoenzymatic strategies and biocatalysts to enable exploration of the sialic acid space.
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影响因子：
4
作者：
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通讯作者：
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影响因子：
12.9
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作者：
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