Effect of chemical modification of histidines on the copper-induced oligomerization of jack bean urease (EC 3.5.1.5)
Effect of chemical modification of histidines on the copper-induced oligomerization of jack bean urease (EC 3.5.1.5)
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DOI：
10.1016/j.abb.2004.12.001
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发表时间：
2005-03-01
影响因子：
3.9
通讯作者：
Carlini, CR
中科院分区：
文献类型：
--
作者：
Follmer, C;Carlini, CR
刀豆脲酶 (JBU) 的聚集与其生物学特性的改变相关，特别是尿素分解和昆虫毒活性。我们研究了金属对蛋白质寡聚和生物特性的影响。除了蛋白质聚集之外，Cu2+ 还能抑制 JBU 的尿素分解和杀虫活性。用焦碳酸二乙酯 (DEPC) 对 JBU 中的组氨酸残基进行化学修饰，降低其对 Cu2+ 的亲和力，并抑制该金属诱导的寡聚化。此外，这种修饰可以保护 JBU 的杀虫特性不被 Cu2+ 灭活。尽管 DEPC 处理的 JBU 显示出较低的尿素分解活性，但与天然酶相比，修饰后的蛋白质更不易受到 Cu2+ 的抑制。我们的研究结果表明，Cu2+ 促进 JBU 聚集，这与本文研究的其他重金属不同。它显然通过诱导蛋白质聚合以及阻断巯基来抑制尿素分解活性。 (C) 2004 Elsevier Inc. 保留所有权利。
Aggregation of jack bean urease (JBU) is associated with alterations of its biological properties, notably the ureolytic and entomotoxic activities. We investigated the influence of metals on protein oligomerization and biological properties. Besides protein aggregation, Cu2+ induces inhibition of both ureolytic and insecticidal activities of JBU. Chemical modification of histidine residues in JBU with diethylpyrocarbonate (DEPC) decreases its affinity for Cu2+ and inhibits oligomerization induced by this metal. Furthermore, this modification protects the insecticidal properties of JBU from being inactivated by Cu2+. Although DEPC-treated JBU displayed lower ureolytic activity, the modified protein is less susceptible to inhibition by Cu2+ when compared to native enzyme. Our findings show that Cu2+ promotes JBU aggregation and differently of other heavy metals studied here. it apparently inhibits the ureolytic activity by inducing protein polymerization along with blockage of sulfhydryl groups. (C) 2004 Elsevier Inc. All rights reserved.