Kinetic characterization and structural modeling of an NAD plus -dependent succinic semialdehyde dehydrogenase from Anabaena sp PCC7120
Kinetic characterization and structural modeling of an NAD plus -dependent succinic semialdehyde dehydrogenase from Anabaena sp PCC7120
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鱼腥藻属 NADP() 依赖性琥珀半醛脱氢酶的动力学特征和结构建模。
DOI：
10.1016/j.ijbiomac.2017.12.059
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发表时间：
2018-03-01
影响因子：
8.2
通讯作者：
Li, Zhimin
中科院分区：
文献类型：
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作者：
Wang, Xiaoqin;lai, Chongde;Li, Zhimin
蓝藻琥珀酸半醛脱氢酶在完成蓝藻三元酸循环中起着关键作用。蓝藻对SSADH的辅因子偏好和催化作用的结构信息目前是可用的。然而，蓝藻SSADH的详细动力学还不是很清楚。在本研究中，从鱼腥藻(Anabaena sp.)中克隆了一个编码SSADH的all3556基因。扩增了PCC7120(ApSSADH)，并对重组ApSSADH进行了纯化。动力学分析表明，ApSSADH是一种依赖NADP(+)的单链构象酶，它以NADP(+)和琥珀酸半醛(SSA)为底物，其活性受到底物琥珀酸半醛的抑制。同时，Ser157残基被发现作为辅因子偏好的决定因素。进一步的研究表明，活性部位残基的突变将大大降低ApSSADH的活性和底物抑制作用。生物信息学分析表明，这些残基在整个SSADHs中高度保守。据我们所知，这是第一个探索蓝藻SSADH详细动力学的报告。(C)2017爱思唯尔B.V.保留所有权利。
Succinic semialdehyde dehydrogenases (SSADH) of cyanobacteria played a pivotal role in completing the cyanobacterial tricarboxylic acid cycle. The structural information of cofactor preference and catalysis for SSADH from cyanobacteria is currently available. However, the detailed kinetics of SSADH from cyanobacteria were not characterized yet. In this study, an all3556 gene encoding SSADH from Anabaena sp. PCC7120 (ApSSADH) was amplified and the recombinant ApSSADH was purified homogenously. Kinetic analysis showed that ApSSADH was an NADP(+)-dependent SSADH, which utilized NADP(+) and succinic semialdehyde (SSA) as its preferred substrates and the activity of ApSSADH was inhibited by its substrate of SSA. At the same time, the Ser157 residue was found to function as the determinant of cofactor preference. Further study demonstrated that activity and substrate inhibition of ApSSADH would be greatly reduced by the mutation of the residues at the active site. Bioinformatic analysis indicated that those residues were highly conserved throughout the SSADHs. To our knowledge this is the first report exploring the detailed kinetics of SSADH from cyanobacteria. (C) 2017 Elsevier B.V. All rights reserved.