Induction of an AP endonuclease activity in Streptococcus mutans during growth at low pH
Induction of an AP endonuclease activity in Streptococcus mutans during growth at low pH
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DOI：
10.1046/j.1365-2958.1999.01292.x
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发表时间：
1999-03-01
影响因子：
3.6
通讯作者：
Quivey, RG
中科院分区：
文献类型：
--
作者：
Hahn, K;Faustoferri, RC;Quivey, RG
口腔微生物变形链球菌使用适应性机制来承受自然环境中pH值的波动。蛋白质合成的调控是变形链球菌酸适应和耐受性机制的一部分。在这里，我们证明了生物体的酸诱导蛋白库包括AP内切酶活性。这种基本的位点特异性内切酶活性在低pH下生长的细胞中比在pH7下生长的细胞中存在更高的水平，并且显然与RecA蛋白无关。使用四氢呋喃或含有α -脱氧腺苷的底物进行的实验表明，在低pH下诱导的活性可能与大肠杆菌的外切酶III的活性相似。在野生型和recA菌株暴露于近紫外线辐射后，酸适应变形链球菌的存活率也有所增加。只有野生型具有抗远紫外线辐射的能力。从pH值为5的S. mutans recA突变株中纯化了大约500倍的内切酶活性。初步鉴定显示了3‘至5’外切酶活性，并显示了其他生物DNA修复酶的功能相似性。
The oral microbe Streptococcus mutans uses adaptive mechanisms to withstand the fluctuating pH levels in its natural environment. The regulation of protein synthesis is part of the mechanism of acid adaptation and tolerance in S. mutans. Here, we demonstrate that the organism's acid-inducible protein repertoire includes an AP endonuclease activity. This abasic site-specific endonuclease activity is present at greater levels in cells grown at low pH than in cells grown at pH7, and is apparently independent of the RecA protein. Experiments using tetrahydrofuran or alpha-deoxyadenosine-containing substrates indicate that the activity induced at low pH may be similar to the activity of exonuclease III from E. coli. Acid-adapted S. mutans also shows an increased survival rate after exposure to near-UV radiation in both the wild type and a recA strain. Far-UV radiation resistance is observed in the wild type only. The endonuclease activity was purified approximate to 500-fold from an S. mutans recA mutant strain grown at pH 5. Initial characterization revealed a 3' to 5' exonuclease activity, and showed additional functional similarities to DNA repair enzymes from other organisms.