Proteome analysis of Streptococcus mutans metabolic phenotype during acid tolerance
Proteome analysis of Streptococcus mutans metabolic phenotype during acid tolerance
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DOI：
10.1099/mic.0.26888-0
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发表时间：
2004-05-01
期刊：
影响因子：
2.8
通讯作者：
Jacques, NA
中科院分区：
文献类型：
--
作者：
Len, MCL;Harty, DWS;Jacques, NA
对在葡萄糖限制的厌氧连续培养物中稳定生长的变形链球菌的蛋白质组进行二维凝胶电泳分析显示，当生长pH值从pH 7.0降低至pH 5.0时，许多蛋白质出现差异表达。代谢蛋白表达的变化通常限于三种生化途径：糖酵解、替代酸产生和支链氨基酸生物合成。鉴定并测量了代表与 Embden-Meyerhof-Parnas 途径相关的所有酶以及除了一种以外的参与变形链球菌主要替代酸发酵途径的所有酶的蛋白点的相对表达水平。蛋白质组数据与最终产物和细胞产量分析相结合，与表型变化一致，该表型变化使变形链球菌能够通过消耗能量从细胞中挤出过量的 H+ 在低 pH 下增殖，同时最大限度地减少分解代谢碳通量解偶联以及随之而来的 NADH 和丙酮酸生产不平衡所造成的有害影响。酶水平的变化与最强酸甲酸形成的减少一致，这是当变形链球菌在酸性环境中培养时丙酮酸转向乳酸和支链氨基酸生产的结果。
Two-dimensional gel electrophoretic analysis of the proteome of Streptococcus mutans grown at a steady state in a glucose-limited anaerobic continuous culture revealed a number of proteins that were differentially expressed when the growth pH was lowered from pH 7.0 to pH 5.0. Changes in the expression of metabolic proteins were generally limited to three biochemical pathways: glycolysis, alternative acid production and branched-chain amino acid biosynthesis. The relative level of expression of protein spots representing all of the enzymes associated with the Embden-Meyerhof-Parnas pathway, and all but one of the enzymes involved in the major alternative acid fermentation pathways of S. mutans, was identified and measured. Proteome data, in conjunction with end-product and cell-yield analyses, were consistent with a phenotypic change that allowed S. mutans to proliferate at low pH by expending energy to extrude excess H+ from the cell, while minimizing the detrimental effects that result from the uncoupling of carbon flux from catabolism and the consequent imbalance in NADH and pyruvate production. The changes in enzyme levels were consistent with a reduction in the formation of the strongest acid, formic acid, which was a consequence of the diversion of pyruvate to both lactate and branched-chain amino acid production when S. mutans was cultivated in an acidic environment.