Pyrophosphate-Dependent ATP Formation from Acetyl Coenzyme A in Syntrophus aciditrophicus, a New Twist on ATP Formation.
Pyrophosphate-Dependent ATP Formation from Acetyl Coenzyme A in Syntrophus aciditrophicus, a New Twist on ATP Formation.
复制标题
乙酰辅酶A中的焦磷酸依赖性ATP形成，在酸性营养性的酸性ATP形成上是一种新的扭曲。
DOI：
10.1128/mbio.01208-16
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发表时间：
2016-08-16
期刊：
影响因子：
6.4
通讯作者：
McInerney MJ
中科院分区：
文献类型：
--
作者：
James KL;Ríos-Hernández LA;Wofford NQ;Mouttaki H;Sieber JR;Sheik CS;Nguyen HH;Yang Y;Xie Y;Erde J;Rohlin L;Karr EA;Loo JA;Ogorzalek Loo RR;Hurst GB;Gunsalus RP;Szweda LI;McInerney MJ
嗜酸互养菌是一种模式互养细菌，当与消耗氢/甲酸盐的微生物一起生长时，其将厌氧分解中的关键中间体（如苯甲酸盐、环己烷-1-羧酸盐和某些脂肪酸）降解为乙酸盐。ATP的形成与乙酸盐的产生是嗜酸链球菌能量守恒的主要来源。然而，在嗜酸链球菌的基因组中缺乏磷酸乙酰转移酶和乙酸激酶的同源物，使得ATP如何形成尚不清楚，因为大多数发酵细菌依赖于这两种酶从乙酰辅酶A（CoA）和磷酸合成ATP。在这里，我们结合联合收割机转录组学，蛋白质组学，代谢物，和酶的方法来表明，S. aciditrophicus使用AMP形成，乙酰辅酶A合成酶（Acs 1）从乙酰辅酶A合成ATP。acs 1 mRNA和Acs 1分别在纯培养和共培养的嗜酸链球菌的转录组和蛋白质组中丰富。嗜酸链球菌的细胞提取物具有低的或检测不到的乙酸激酶和磷酸乙酰转移酶活性，但在所有测试的生长条件下具有高的乙酰辅酶A合成酶活性。从嗜酸链球菌纯化的Acs 1和重组产生的Acs 1都催化乙酰辅酶A、AMP和焦磷酸盐形成ATP和乙酸盐。在嗜酸链球菌细胞中，高焦磷酸盐水平和高AMP/ATP比率（5.9 ± 1.4）支持Acs 1在乙酸盐形成方向上的操作。因此，嗜酸链球菌有一种独特的方法来保存能量，涉及焦磷酸盐、AMP、乙酰辅酶A和形成AMP的乙酰辅酶A合成酶。细菌使用两种酶，磷酸乙酰转移酶和乙酸激酶，从乙酰辅酶A合成ATP，而乙酸形成古细菌使用一种酶，ADP形成，乙酰辅酶A合成酶，从乙酰辅酶A合成ATP和乙酸。Syntrophus aciditrophicus显然依赖于不同的方法来保存乙酰辅酶A代谢过程中的能量，因为它的基因组没有同源的磷酸乙酰转移酶和乙酸激酶的基因。在这里，我们表明，S. aciditrophicus使用另一种方法，AMP形成，乙酰辅酶A合成酶，使ATP从乙酰辅酶A。形成AMP的乙酰辅酶A合成酶以前被认为仅在乙酸活化为乙酰辅酶A中起作用。
Syntrophus aciditrophicus is a model syntrophic bacterium that degrades key intermediates in anaerobic decomposition, such as benzoate, cyclohexane-1-carboxylate, and certain fatty acids, to acetate when grown with hydrogen-/formate-consuming microorganisms. ATP formation coupled to acetate production is the main source for energy conservation by S. aciditrophicus. However, the absence of homologs for phosphate acetyltransferase and acetate kinase in the genome of S. aciditrophicus leaves it unclear as to how ATP is formed, as most fermentative bacteria rely on these two enzymes to synthesize ATP from acetyl coenzyme A (CoA) and phosphate. Here, we combine transcriptomic, proteomic, metabolite, and enzymatic approaches to show that S. aciditrophicus uses AMP-forming, acetyl-CoA synthetase (Acs1) for ATP synthesis from acetyl-CoA. acs1 mRNA and Acs1 were abundant in transcriptomes and proteomes, respectively, of S. aciditrophicus grown in pure culture and coculture. Cell extracts of S. aciditrophicus had low or undetectable acetate kinase and phosphate acetyltransferase activities but had high acetyl-CoA synthetase activity under all growth conditions tested. Both Acs1 purified from S. aciditrophicus and recombinantly produced Acs1 catalyzed ATP and acetate formation from acetyl-CoA, AMP, and pyrophosphate. High pyrophosphate levels and a high AMP-to-ATP ratio (5.9 ± 1.4) in S. aciditrophicus cells support the operation of Acs1 in the acetate-forming direction. Thus, S. aciditrophicus has a unique approach to conserve energy involving pyrophosphate, AMP, acetyl-CoA, and an AMP-forming, acetyl-CoA synthetase. Bacteria use two enzymes, phosphate acetyltransferase and acetate kinase, to make ATP from acetyl-CoA, while acetate-forming archaea use a single enzyme, an ADP-forming, acetyl-CoA synthetase, to synthesize ATP and acetate from acetyl-CoA. Syntrophus aciditrophicus apparently relies on a different approach to conserve energy during acetyl-CoA metabolism, as its genome does not have homologs to the genes for phosphate acetyltransferase and acetate kinase. Here, we show that S. aciditrophicus uses an alternative approach, an AMP-forming, acetyl-CoA synthetase, to make ATP from acetyl-CoA. AMP-forming, acetyl-CoA synthetases were previously thought to function only in the activation of acetate to acetyl-CoA.