Activity of plasma membrane H+-ATPase and expression of PMA1 and PMA2 genes in Saccharomyces cerevisiae cells grown at optimal and low pH
Activity of plasma membrane H+-ATPase and expression of PMA1 and PMA2 genes in Saccharomyces cerevisiae cells grown at optimal and low pH
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DOI：
10.1007/s002030050389
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发表时间：
1996-11-01
影响因子：
2.8
通讯作者：
SaCorreia, I
中科院分区：
文献类型：
--
作者：
Carmelo, V;Bogaerts, P;SaCorreia, I
酿酒酵母细胞在初始pH为2.5-6.0的培养基中生长，并用强酸(HCl)酸化，在初始pH为6.0时表现出最高的质膜H+-ATP酶特异性活性。在较低 pH 值（pH 2.5 以上）下，ATP 酶活性（最高水平的 62-83%）仍可实现最佳生长。 pH 2.5 时，ATP 酶活性约为最大值的 30%，生长受到损害。定量免疫测定表明，在整个测试的 pH 范围内，质膜中 ATP 酶蛋白的含量相似，尽管在 pH 2.5 时稍低。在低 pH 下生长的细胞中质膜 ATP 酶活性的降低部分是由于其体外稳定性，在 pH 低于 5.5 时急剧下降，尽管活性的降低远低于体外测量的预期值。酸胁迫下酵母的生长改变了在最佳 pH 值下观察到的基因表达模式。与在最佳 pH 5.0 下生长的细胞相比，在 pH 2.5 下生长的细胞中，来自必需质膜 ATP 酶编码基因 PMA1 的 mRNA 水平降低了 50%，尽管质膜中 ATP 酶的含量仅略有降低。正如在响应其他类型胁迫时观察到的，在最佳 pH 下生长的细胞中，PMA2 启动子的效率高达 8 倍，尽管其效率仍然比在 pH 2.5 下生长的细胞低数百倍。 PMA1 基因。
Cells of Saccharomyces cerevisiae grown in media with an initial pH of 2.5-6.0, acidified with a strong acid (HCl), exhibited the highest plasma membrane H+-ATPase-specific activity at an initial pH of 6.0. At a lower pH (above pH 2.5) ATPase activity (62-83% of the maximum level) still allowed optimal growth. At pH 2.5, ATPase activity was about 30% of the maximum value and growth was impaired. Quantitative immunoassays showed that the content of ATPase protein in the plasma membrane was similar across the entire pH range tested, although slightly lower at pH 2.5, The decrease of plasma membrane ATPase activity in cells grown at low pH was partially accounted for by its in vitro stability, which decreased sharply at pH below 5.5, although the reduction of activity was far below the values expected from in vitro measurements. Yeast growth under acid stress changed the pattern of gene expression observed at optimal pH. The level of mRNA from the essential plasma-membrane-ATPase-encoding gene PMA1 was reduced by 50% in cells grown at pH 2.5 as compared with cells grown at the optimal pH 5.0, although the content of ATPase in the plasma membrane was only modestly reduced, As observed in response to other kinds of stress, the PMA2 promoter at the optimal pH was up to eightfold more efficient in cells grown at pH 2.5, although it remained several hundred times less efficient than that of the PMA1 gene.