Propionyl Coenzyme A (Propionyl-CoA) Carboxylase in Haloferax mediterranei: Indispensability for Propionyl-CoA Assimilation and Impacts on Global Metabolism
Propionyl Coenzyme A (Propionyl-CoA) Carboxylase in Haloferax mediterranei: Indispensability for Propionyl-CoA Assimilation and Impacts on Global Metabolism
复制标题
Haloferax mediterranei 中的丙酰辅酶 A (丙酰-CoA) 羧化酶：丙酰-CoA 同化的必要性及其对整体代谢的影响
DOI：
10.1128/aem.03167-14
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发表时间：
2015-01-01
影响因子：
4.4
通讯作者：
Han, Jing
中科院分区：
文献类型：
--
作者：
Hou, Jing;Xiang, Hua;Han, Jing
摘要丙酰辅酶A（propionyl-CoA）是嗜盐古菌生物合成和催化胞内碳储存聚3-羟基丁酸-co-3-羟基戊酸酯（PHBV）的重要中间体。然而，盐古菌丙酰辅酶A羧化酶（PCC）及其生理意义尚不清楚。在这项研究中，我们确定了PCC，催化丙酰辅酶A羧化与乙酰辅酶A羧化的副活性在地中海盐藻。基因敲除/互补证明PCC酶由生物素羧化酶和生物素-羧基载体蛋白的融合蛋白（PccA [HFX_2490]）、羧基转移酶组分（PccB [HFX_2478]）和必需小亚基（PccX [HFX_2479]）组成。敲除pccBX导致不能利用丙酸和更高的细胞内丙酰辅酶A水平，表明PCC酶是必不可少的丙酰辅酶A利用。有趣的是，H。mediobaseiDBX（pccBX缺失菌株）显示出多种表型变化，包括细胞生长迟缓、葡萄糖消耗减少、PHBV生物合成受损和细胞起皱。丙酰辅酶A浓度相当于DBX细胞中积累的浓度，证明在体外抑制三羧酸循环的琥珀酰辅酶A合成酶。全基因组微阵列分析表明，许多基因的糖酵解，丙酮酸氧化，PHBV积累，电子传递和应激反应的影响DBX。本研究不仅鉴定了盐古菌PCC对盐古菌重要中间产物丙酰辅酶A的代谢，而且证明了丙酰辅酶A代谢受损会影响盐古菌的整体代谢。医生。
ABSTRACT Propionyl coenzyme A (propionyl-CoA) is an important intermediate during the biosynthesis and catabolism of intracellular carbon storage of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) in haloarchaea. However, the haloarchaeal propionyl-CoA carboxylase (PCC) and its physiological significance remain unclear. In this study, we identified a PCC that catalyzed propionyl-CoA carboxylation with an acetyl-CoA carboxylation side activity in Haloferax mediterranei. Gene knockout/complementation demonstrated that the PCC enzyme consisted of a fusion protein of a biotin carboxylase and a biotin-carboxyl carrier protein (PccA [HFX_2490]), a carboxyltransferase component (PccB [HFX_2478]), and an essential small subunit (PccX [HFX_2479]). Knockout of pccBX led to an inability to utilize propionate and a higher intracellular propionyl-CoA level, indicating that the PCC enzyme is indispensable for propionyl-CoA utilization. Interestingly, H. mediterranei DBX (pccBX-deleted strain) displayed multiple phenotypic changes, including retarded cell growth, decreased glucose consumption, impaired PHBV biosynthesis, and wrinkled cells. A propionyl-CoA concentration equivalent to the concentration that accumulated in DBX cells was demonstrated to inhibit succinyl-CoA synthetase of the tricarboxylic acid cycle in vitro. Genome-wide microarray analysis showed that many genes for glycolysis, pyruvate oxidation, PHBV accumulation, electron transport, and stress responses were affected in DBX. This study not only identified the haloarchaeal PCC for the metabolism of propionyl-CoA, an important intermediate in haloarchaea, but also demonstrated that impaired propionyl-CoA metabolism affected global metabolism in H. mediterranei.