An unprecedented insight into the catalytic mechanism of copper nitrite reductase from atomic-resolution and damage-free structures.
An unprecedented insight into the catalytic mechanism of copper nitrite reductase from atomic-resolution and damage-free structures.
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DOI：
10.1126/sciadv.abd8523
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发表时间：
2021-01
期刊：
影响因子：
13.6
通讯作者：
Hasnain SS
中科院分区：
文献类型：
--
作者：
Rose SL;Antonyuk SV;Sasaki D;Yamashita K;Hirata K;Ueno G;Ago H;Eady RR;Tosha T;Yamamoto M;Hasnain SS
高精度的SR结构和无损伤的XFEL结构为CuNiR的催化机理提供了详细的见解。含铜亚硝酸还原酶(CuNiRs)由nirK基因编码，存在于所有的生物王国中，只有5%的CuNiR反硝化酶具有两个或两个以上的nirK拷贝。最近，我们已经在包括慢生根瘤菌在内的根瘤目的几种α蛋白细菌中发现了两个拷贝的nirk基因。ORS 375，编码四个结构域的血红素-CuNiR和通常的两个结构域的CuNiR(Br2DNiR)。与以蓝色(AxNiR)和绿色(AcNiR)亚类为代表的两个结构域CuNiR相比，蓝色CuNiR Br2DNiR的催化效率要低得多，尽管序列同源性约为70%。先进的同步辐射和x射线自由电子激光被用来获得最精确的(原子分辨率不受限制的SHELX精细化)和无损伤(不受辐射诱导的化学作用)的结构，在As隔离状态、衬底约束状态和产品约束状态下。这一组合揭示了基本催化残基、额外反应中间体的质子化状态，以及催化效率是如何调节的。
Highly accurate SR structures and damage-free XFEL structures provide detailed insight into catalytic mechanism of CuNiR. Copper-containing nitrite reductases (CuNiRs), encoded by nirK gene, are found in all kingdoms of life with only 5% of CuNiR denitrifiers having two or more copies of nirK. Recently, we have identified two copies of nirK genes in several α-proteobacteria of the order Rhizobiales including Bradyrhizobium sp. ORS 375, encoding a four-domain heme-CuNiR and the usual two-domain CuNiR (Br2DNiR). Compared with two of the best-studied two-domain CuNiRs represented by the blue (AxNiR) and green (AcNiR) subclasses, Br2DNiR, a blue CuNiR, shows a substantially lower catalytic efficiency despite a sequence identity of ~70%. Advanced synchrotron radiation and x-ray free-electron laser are used to obtain the most accurate (atomic resolution with unrestrained SHELX refinement) and damage-free (free from radiation-induced chemistry) structures, in as-isolated, substrate-bound, and product-bound states. This combination has shed light on the protonation states of essential catalytic residues, additional reaction intermediates, and how catalytic efficiency is modulated.
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系列晶体学以原子分辨率从一个晶体捕获亚硝酸铜还原酶的酶催化作用。
影响因子：
3.9
作者：
Horrell S;Antonyuk SV;Eady RR;Hasnain SS;Hough MA;Strange RW
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DOI：
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发表时间：
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影响因子：
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DOI：
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发表时间：
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影响因子：
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