Carboxy-terminal modification of polyhydroxyalkanoate (PHA) via alcoholysis reaction catalyzed by Class IV PHA synthase
Carboxy-terminal modification of polyhydroxyalkanoate (PHA) via alcoholysis reaction catalyzed by Class IV PHA synthase
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DOI：
10.1016/j.polymdegradstab.2015.04.002
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发表时间：
2015-07-01
影响因子：
5.9
通讯作者：
Tsuge, Takeharu
中科院分区：
文献类型：
--
作者：
Hyakutake, Manami;Tomizawa, Satoshi;Tsuge, Takeharu
来自蜡样芽孢杆菌 YB-4 细菌的聚羟基烷酸酯 (PHA) 合酶 (PhaRC(YB4)) 是一种 IV 类 PHA 合酶，具有 PHA 聚合和醇解活性。在乙醇存在下表达 PhaRC(YB4) 的大肠杆菌中，由于 PhaRC(YB4) 对 PHA 链进行醇解裂解，生物合成的 PHA 在羧基末端发生乙酯化。在这项研究中，我们通过在两步培养的第二步过程中监测 PHA 的分子量，研究了 PhaRC(YB4) 使用大肠杆菌 JM109 作为测定宿主可进行醇解的醇种类的范围。 PhaRC(YB4)利用乙醇以外的各种醇进行醇解。通过使用双官能化合物进行醇解，可以用硫醇、炔基、羟基和苄基修饰PHA羧基末端，从而实现PHA羧基末端的功能化。此外，使用大肠杆菌 XL1-Blue 作为生产宿主，开发了羧基末端功能化 PHA 的一步生产。 (c) 2015 Elsevier Ltd. 保留所有权利。
Polyhydroxyalkanoate (PHA) synthase from the bacterium Bacillus cereus YB-4 (PhaRC(YB4)), a class IV PHA synthase, shows both PHA polymerization and alcoholysis activities. In PhaRC(YB4)-expressing Escherichia coli in the presence of ethanol, biosynthesized PHA is subjected to an ethyl-esterification at the carboxy terminus as a result of alcoholytic cleavage of the PHA chain by PhaRC(YB4). In this study, we investigated the range of alcohol species available for alcoholysis by PhaRC(YB4) using E. coli JM109 as an assay host by monitoring the molecular weight of PHA during the second step of a two-step cultivation. PhaRC(YB4) utilized various alcohols other than ethanol for alcoholysis. Through the use of bifunctional compounds for alcoholysis, the PHA carboxy terminus could be modified with thiol, alkynyl, hydroxy, and benzyl groups, resulting in the functionalization of the PHA carboxy terminus. Furthermore, one-step production of carboxy-terminal functionalized PHA was developed using E. coli XL1-Blue as a production host. (c) 2015 Elsevier Ltd. All rights reserved.