Structure and function of urea amidolyase.
Structure and function of urea amidolyase.
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尿素酰胺裂解酶的结构和功能。
DOI：
10.1042/bsr20171617
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Xiang Song
中科院分区：
文献类型：
--
作者：
Zhao Jing;Zhu Li;Fan Chen;Wu Yi;Xiang Song
尿素是多种含氮生物分子的降解产物。尿素氨解酶(UA)催化尿素转化为氨，这是利用尿素作为氮源的重要第一步。它广泛分布于真菌、细菌等微生物体内，在生物圈氮素循环中起着重要作用。尿酸是由尿素羧基酶(UC)和尿氨酸水解酶(AH)结构域组成，催化一系列反应。在一些生物中，UC和AH是由不同的基因编码的。本文介绍了乳酸克鲁维酵母UA(KlUA)的结构。结构分析表明，KlUA形成了一个致密的均二聚体，其相对分子质量为400 kDa。结构启发的生化实验揭示了其反应中间体易位的机制，KlUA全酶的形成是其最佳活性所必需的。有趣的是，以前的研究和我们的研究都表明，由分离的基因编码的UC和AH可能不会形成KlUA样的复合体，因此它们可能不能有效地催化尿素向铵的转化。
Urea is the degradation product of a wide range of nitrogen containing bio-molecules. Urea amidolyase (UA) catalyzes the conversion of urea to ammonium, the essential first step in utilizing urea as a nitrogen source. It is widely distributed in fungi, bacteria and other microorganisms, and plays an important role in nitrogen recycling in the biosphere. UA is composed of urea carboxylase (UC) and allophanate hydrolase (AH) domains, which catalyze sequential reactions. In some organisms UC and AH are encoded by separated genes. We present here structure of theKluyveromyces lactis UA(KlUA). The structure revealed that KlUA forms a compact homo-dimer with a molecular weight of 400 kDa. Structure inspired biochemical experiments revealed the mechanism of its reaction intermediate translocation, and that the KlUA holo-enzyme formation is essential for its optimal activity. Interestingly, previous studies and ours suggest that UC and AH encoded by separated genes probably do not form a KlUA-like complex, consequently they might not catalyze the urea to ammonium conversion as efficiently.