Fan Hsiu-Fang, Su Shu, Kuo Ying-An, Chen Cyuan-Ji
Institute of Medical Science and Technology, National Sun Yat-sen University, Kaohsiung 80424, Taiwan.
Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan.
ACS Omega. 2020 Aug 3;5(31):19868-19876. doi: 10.1021/acsomega.0c02865. eCollection 2020 Aug 11.
--, resistant to ultraviolet, ionizing radiation, and chemicals which may cause DNA damage, was identified in Taiwan. The expression level of RecA, which has 92% sequence identity with () RecA, will be upregulated upon UV radiation. Multiple sequence alignment of RecA proteins from bacteria belonging to and the genus reveals that the C-terminal tail of RecA is shorter and contains less acidic residues than RecA. RecA exhibits a higher ATPase activity toward single-stranded (ss) DNA and efficiently promotes DNA strand exchange that a filament is first formed on ssDNA, followed by uptake of the double-stranded (ds) substrate. Moreover, RecA exhibits a pH-reaction profile for DNA strand exchange similar to Δ RecA. Later, a chimera RecA with more acidic residues in the C-terminal tail was constructed and purified. Increased negativity in the C-terminal tail makes the pH reaction profile for Chimera RecA DNA strand exchange exhibit a reaction optimum similar to RecA. To sum up, RecA exhibits reaction properties in substrate-dependent ATPase activity and DNA strand exchange similar to RecA. Our data indicate that the negativity in the C-terminal tail plays an important role in the regulation of pH-dependent DNA strand exchange activity.
在台湾发现了一种对紫外线、电离辐射和可能导致DNA损伤的化学物质具有抗性的物质。与（）RecA具有92%序列同一性的RecA的表达水平在紫外线辐射后会上调。对属于和属的细菌的RecA蛋白进行多序列比对发现，RecA的C末端尾巴比RecA短，且酸性残基更少。RecA对单链（ss）DNA表现出更高的ATP酶活性，并能有效地促进DNA链交换，即首先在ssDNA上形成细丝，然后摄取双链（ds）底物。此外，RecA对DNA链交换表现出与ΔRecA相似的pH反应曲线。后来，构建并纯化了一种在C末端尾巴中含有更多酸性残基的嵌合体RecA。C末端尾巴中负电荷的增加使得嵌合体RecA DNA链交换反应的pH曲线呈现出与RecA相似的反应最佳值。综上所述，RecA在底物依赖性ATP酶活性和DNA链交换方面表现出与RecA相似的反应特性。我们的数据表明，C末端尾巴中的负电荷在pH依赖性DNA链交换活性的调节中起重要作用。
