CHARACTERIZATION OF A GENE RESPONSIBLE FOR THE NA+/H+ ANTIPORTER SYSTEM OF ALKALOPHILIC BACILLUS SPECIES STRAIN C-125
CHARACTERIZATION OF A GENE RESPONSIBLE FOR THE NA+/H+ ANTIPORTER SYSTEM OF ALKALOPHILIC BACILLUS SPECIES STRAIN C-125
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DOI：
10.1111/j.1365-2958.1994.tb01329.x
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发表时间：
1994-12-01
影响因子：
3.6
通讯作者：
HORIKOSHI, K
中科院分区：
文献类型：
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作者：
HAMAMOTO, T;HASHIMOTO, M;HORIKOSHI, K
嗜碱芽孢杆菌属的碱敏感突变体 38154。菌株 C-125 不能在碱性 pH 值下生长。在碱性 pH 下恢复 38154 生长的 3.7 kb 亲本 DNA 片段的核苷酸序列有四个开放阅读框 (ORF1-4)。通过亚克隆该片段，我们证明了 0.25 kb DNA 区域负责恢复。对突变体相应区域的直接测序揭示了 G 到 A 的取代。该突变导致假定的 ORF1 产物的氨基酸从 Gly-393 替换为 Arg，推测 ORF1 产物是一条 804 个氨基酸的多肽，分子量为 89070。假定的 ORF1 产物的 N 端部分与真核 NADH 醌氧化还原酶的 chain-5 产物的氨基酸相似。由 38154 制备的膜囊泡未表现出膜电位 (Delta psi) 驱动的 Na+/H+ 反向转运蛋白活性。通过引入恢复突变体嗜碱性的亲本DNA片段来恢复逆向转运蛋白活性。这些结果表明 38154 中的突变直接或间接影响产电 Na+/H+ 逆向转运蛋白活性。这是第一份表明负责Na+/H+逆向转运蛋白系统的基因在嗜碱微生物的嗜碱性中很重要的报告。
An alkali-sensitive mutant, 38154, of the alkalophilic Bacillus sp. strain C-125 could not grow at an alkaline pH. The nucleotide sequence of a 3.7 kb parental DNA fragment that recovers the growth of 38154 at alkaline pH has four open reading frames (ORF1-4). By subcloning the fragment, we demonstrated that a 0.25 kb DNA region is responsible for the recovery. Direct sequencing of the mutant's corresponding region revealed a G to A substitution. The mutation resulted in an amino acid substitution from Gly-393 to Arg of the putative ORF1 product, which was deduced to be an 804-amino-acid polypeptide with a molecular weight of 89070. The N-terminal part of the putative ORF1 product showed amino acid similarity to those of the chain-5 products of eukaryotic NADH quinone oxidoreductases. Membrane vesicles prepared from 38154 did not show membrane potential (Delta psi)-driven Na+/H+ antiporter activity. Antiporter activity was resumed by introducing a parental DNA fragment which recovered the mutant's alkalophily. These results indicate that the mutation in 38154 affects, either directly or indirectly, the electrogenic Na+/H+ antiporter activity. This is the first report which shows that a gene responsible for the Na+/H+ antiporter system is important in the alkalophily of alkalophilic microorganisms.