Formation of an Organic-Inorganic Biopolymer: Polyhydroxybutyrate-Polyphosphate
Formation of an Organic-Inorganic Biopolymer: Polyhydroxybutyrate-Polyphosphate
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DOI：
10.1021/acs.biomac.9b00208
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发表时间：
2019-09-01
影响因子：
6.2
通讯作者：
Jendrossek, Dieter
中科院分区：
文献类型：
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作者：
Hildenbrand, Jennie C.;Reinhardt, Simone;Jendrossek, Dieter
地球上存在的全部有机体形成了相当多种类的不同生物聚合物。这些化合物大多是有机聚合物，如多糖、多氨基酸、多核苷酸、多异戊二烯或聚羟基烷酸酯(PHAs)，但一些生物聚合物可以只由无机单体组成，如聚磷酸盐(Polyps)中的磷酸盐。在这篇文章中，我们描述了一种由聚(3-羟基丁酸酯)(PHB)和聚(聚)磷组成的有机-无机嵌段共聚物的形成。这是通过在无息肉和无PHB突变背景的R富营养菌中表达聚合酶基因(Ppk2c)和PHB合成酶基因(Phac)来实现的。融合蛋白通过其息肉激活区催化息肉的形成，并通过其PHB合成酶结构域催化PHB的形成。如果提供三磷酸腺苷(ATP)和3-羟基丁酰辅酶A(3HB-CoA)这两种单体，用纯化的Ppk2c-PHAC也可以在体外合成Polyp-PHB聚合物。最有可能的是，形成的嵌段共聚物(Polyp-Protein-PHB)从酶中释放出来后变成了Polyp和PHB的混合物。
A considerable variety of different biopolymers is formed by the entirety of organisms present on earth. Most of these compounds are organic polymers such as polysaccharides, polyamino acids, polynucleotides, polyisoprenes or polyhydroxyalkanoates (PHAs), but some biopolymers can consist of solely inorganic monomers such as phosphate in polyphosphates (polyPs). In this contribution, we describe the formation of an organic-inorganic block copolymer consisting of poly(3-hydroxybutyrate) (PHB) and polyP. This was achieved by the expression of a fusion of the polyP kinase gene (ppk2c) with the PHB synthase gene (phaC) of Ralstonia eutropha in a polyP-free and PHB-free mutant background of R eutropha. The fusion protein catalyzed both the formation of polyP by its polyP kinase domain and the formation of PHB by its PHB synthase domain. It was also possible to synthesize the polyP-PHB polymer in vitro with purified Ppk2c-PhaC, if the monomers, adenosine triphosphate (ATP) and 3-hydroxybutyryl-CoA (3HB-CoA), were provided. Most likely, the formed block copolymer (polyP-protein-PHB) turns into a blend of polyP and PHB after release from the enzyme.