Kimura Yoshio, Kajimoto Sayaka, Yamamoto Yuuka, Tanaka Naotaka
Department of Applied Biological Science, Faculty of Agriculture, Kagawa University.
J Gen Appl Microbiol. 2020 Apr 13;66(1):46-50. doi: 10.2323/jgam.2019.04.002. Epub 2019 Jul 9.
Myxococcus xanthus Nudix hydrolase 2 (Nud2) hydrolyzed oxidized deoxynucleotides, such as 8-oxo-dGTP, 8-oxo-dGDP, 8-OH-dTP, and 2-OH-dATP, and showed the highest specific activity toward 8-oxo-dGTP. Mn was the most effective co-factor for stimulating oxidized deoxynucleotide hydrolase activity. The K of Nud2 with 8-oxo-dGTP for Mn was 19-fold lower than that for Mg, and was 2-fold lower than that with dGTP for Mn. The specificity constant (k/K) for 8-oxo-dGTP was 6-fold higher than that for dGTP. Nud2 contains a similar Nudix motif (AXGXREXEEXGX). Replacement of Ala84 and/or Gly90 in the Nudix motif of Nud2 by Gly or Glu had negligible effects on 8-oxo-dGTP hydrolase activity, suggesting that a strict Nudix motif sequence is not essential for complete hydrolase activity of Nud2.
黄色粘球菌Nudix水解酶2（Nud2）可水解氧化的脱氧核苷酸，如8-氧代-dGTP、8-氧代-dGDP、8-羟基-dTP和2-羟基-dATP，并且对8-氧代-dGTP表现出最高的比活性。锰是刺激氧化脱氧核苷酸水解酶活性最有效的辅助因子。Nud2与8-氧代-dGTP结合时对锰的K值比对镁的K值低19倍，比对dGTP结合锰时的K值低2倍。8-氧代-dGTP的特异性常数（k/K）比dGTP高6倍。Nud2含有一个类似的Nudix基序（AXGXREXEEXGX）。将Nud2的Nudix基序中的Ala84和/或Gly90替换为Gly或Glu对8-氧代-dGTP水解酶活性的影响可忽略不计，这表明严格的Nudix基序序列对于Nud2的完全水解酶活性并非必不可少。
