Structural and Kinetic Characterization of Hyperthermophilic NADH-Dependent Persulfide Reductase from Archaeoglobus fulgidus.
Structural and Kinetic Characterization of Hyperthermophilic NADH-Dependent Persulfide Reductase from Archaeoglobus fulgidus.
复制标题
古球藻NADH依赖的高温过硫化物还原酶的结构和动力学特征。
DOI：
10.1155/2021/8817136
复制
发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Sazinsky MH
中科院分区：
文献类型：
--
作者：
Shabdar S;Anaclet B;Castineiras AG;Desir N;Choe N;Crane EJ 3rd;Sazinsky MH
NADH依赖的过硫化物还原酶(NPSR)通过将含硫或硫磺的底物还原为H_2S来促进异化硫呼吸。该基因在硫酸盐和硫代硫酸盐还原的黄腐菌DSM 4304和其他嗜热古球藻中的存在似乎是异常的，因为黄腐菌不能呼吸S0并在元素硫存在下生长。为了研究NpsR在硫杆菌DSM 4304硫代谢中的作用，对黄曲霉的Npsr进行了鉴定。在氧化半反应中，AFNpsr是以过硫化物和多硫化物为底物的特异酶，其kcat/Km约为104M−1 S−1，与高温CoA过硫化物还原酶的动力学参数相似。与细菌Npsr相反，AfNpsr对DTNB表现出较低的二硫键还原酶活性；然而，与细菌酶类似，它与CoA-二硫化物、氧化谷胱甘肽或半胱氨酸不显示出可检测到的活性。AfNpsr的3.1äX射线结构揭示了与紧密结合的催化CoA的联系，而活性部位Cys 42受到柔性环(残基60-66)的限制，这在罗氏希瓦氏杆菌PV-4和炭疽杆菌的细菌同源物中不存在。与细菌酶不同，AfNpsr显示出NADH氧化酶活性，也没有显示出与NADPH一起检测到的活性。模型表明，NADPH 2‘-磷酸的空间和静电斥力是NADH的强烈偏好的原因。Npsr在非硫还原硫杆菌中的存在表明，该酶可能对S0提供了一些保护作用，或者起到了另一种尚未确定的代谢作用。
NADH-dependent persulfide reductase (Npsr) has been proposed to facilitate dissimilatory sulfur respiration by reducing persulfide or sulfane sulfur-containing substrates to H2S. The presence of this gene in the sulfate and thiosulfate-reducing Archaeoglobus fulgidus DSM 4304 and other hyperthermophilic Archaeoglobales appears anomalous, as A. fulgidus is unable to respire S0 and grow in the presence of elemental sulfur. To assess the role of Npsr in the sulfur metabolism of A. fulgidus DSM 4304, the Npsr from A. fulgidus was characterized. AfNpsr is specific for persulfide and polysulfide as substrates in the oxidative half-reaction, exhibiting kcat/Km on the order of 104 M−1 s−1, which is similar to the kinetic parameters observed for hyperthermophilic CoA persulfide reductases. In contrast to the bacterial Npsr, AfNpsr exhibits low disulfide reductase activity with DTNB; however, similar to the bacterial enzymes, it does not show detectable activity with CoA-disulfide, oxidized glutathione, or cystine. The 3.1 Å X-ray structure of AfNpsr reveals access to the tightly bound catalytic CoA, and the active site Cys 42 is restricted by a flexible loop (residues 60-66) that is not seen in the bacterial homologs from Shewanella loihica PV-4 and Bacillus anthracis. Unlike the bacterial enzymes, AfNpsr exhibits NADH oxidase activity and also shows no detectable activity with NADPH. Models suggest steric and electrostatic repulsions of the NADPH 2′-phosphate account for the strong preference for NADH. The presence of Npsr in the nonsulfur-reducing A. fulgidus suggests that the enzyme may offer some protection against S0 or serve in another metabolic role that has yet to be identified.
登录
查看更多内容
影响因子：
2.9
作者：
Mallett, T. Conn;Wallen, Jamie R.;Claiborne, Al
通讯作者：
Claiborne, Al
DOI：
10.1021/i260074a018
发表时间：
1980-01-01
期刊：
INDUSTRIAL & ENGINEERING CHEMISTRY PROCESS DESIGN AND DEVELOPMENT
影响因子：
--
作者：
CRAMER, SD
通讯作者：
CRAMER, SD
影响因子：
2.9
作者：
Herwald, Sanna;Liu, Albert Y.;Crane, Edward J., III
通讯作者：
Crane, Edward J., III
影响因子：
5.6
作者：
KARPLUS, PA;SCHULZ, GE
通讯作者：
SCHULZ, GE
影响因子：
3.2
作者：
Takumi, Kazuhiro;Nonaka, Gen
通讯作者：
Nonaka, Gen