Comparative analysis of depurination catalyzed by ricin A-chain on synthetic 32mer and 25mer oligoribonucleotides mimicking the sarcin/ricin domain of the rat 28S rRNA and E. coli 23S rRNA
Comparative analysis of depurination catalyzed by ricin A-chain on synthetic 32mer and 25mer oligoribonucleotides mimicking the sarcin/ricin domain of the rat 28S rRNA and E. coli 23S rRNA
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模拟大鼠 28S rRNA 和大肠杆菌 23S rRNA 的八叠球菌毒素/蓖麻毒素结构域的合成 32 聚体和 25 聚体寡核糖核苷酸上蓖麻毒素 A 链催化脱嘌呤的比较分析
DOI：
10.1016/j.jbiotec.2008.10.005
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发表时间：
2009-01-15
影响因子：
4.1
通讯作者：
Li, Rong-Xiu
中科院分区：
文献类型：
--
作者：
Tan, Qing-Qiao;Dong, De-Xian;Li, Rong-Xiu
Ricin A-chain can inactivate eukaryotic ribosomes, but exhibits no N-glycosidase activity on intact E. coli ribosomes. In the present research, in order to avoid using radiolabeled oligoribonucleotides, two kinds of synthetic 5'-FAM fluorescence-labeled oligoribonucleotide substrates were used to mimic the sarcin/ricin domains of rat 28S rRNA and E. coli 23S rRNA (32mer and 25mer, named as Rat FAM-SRD and E. coli FAM-SRD, respectively). Ricin A-chain was able to specifically release adenine from the first adenosine of the GAGA tetraloop and exhibited specific N-glycosidase activity under neutral and weak acidic conditions with both substrates. However, under more acidic conditions, ricin A-chain was able to release purines from other sites on eukaryotic substrates. but it retained specific depurination activity on prokaryotic substrates. At pH 5.0, the Michaelis constant (K-m) for the reaction with Rat FAM-SRD (4.57 +/- 0.28 mu M) corresponded to that with E coli FAM-SRD (4.64 +/- 0.26 mu M). However, the maximum velocity (V-max) for ricin A-chain with Rat FAM-SRD was 0.5 +/- 0.024 mu M/min, which is higher than that with E coli FAM-SRD (0.32 +/- 0.011 mu M/min). (C) 2008 Elsevier BY. All rights reserved.
