铁氧化还原蛋白：NADP还原酶超家族中氢化物转移的高分辨率研究。
High-resolution studies of hydride transfer in the ferredoxin:NADP reductase superfamily.
作者信息
Kean Kelsey M, Carpenter Russell A, Pandini Vittorio, Zanetti Giuliana, Hall Andrea R, Faber Rick, Aliverti Alessandro, Karplus P Andrew
机构信息
Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, USA.
Department of Biosciences, Università degli Studi di Milano, Italy.
出版信息
FEBS J. 2017 Oct;284(19):3302-3319. doi: 10.1111/febs.14190. Epub 2017 Aug 29.
UNLABELLED
Ferredoxin: NADP reductase (FNR) is an FAD-containing enzyme best known for catalysing the transfer of electrons from ferredoxin (Fd) to NADP to make NADPH during photosynthesis. It is also the prototype for a broad enzyme superfamily, including the NADPH oxidases (NOXs) that all catalyse similar FAD-enabled electron transfers between NAD(P)H and one-electron carriers. Here, we define further mechanistic details of the NAD(P)H ⇌ FAD hydride-transfer step of the reaction based on spectroscopic studies and high-resolution (~ 1.5 Å) crystallographic views of the nicotinamide-flavin interaction in crystals of corn root FNR Tyr316Ser and Tyr316Ala variants soaked with either nicotinamide, NADP , or NADPH. The spectra obtained from FNR crystal complexes match those seen in solution and the complexes reveal active site packing interactions and patterns of covalent distortion of the FAD that imply significant active site compression that would favour catalysis. Furthermore, anisotropic B-factors show that the mobility of the C4 atom of the nicotinamide in the FNR:NADP complex has a directionality matching that expected for boat-like excursions of the nicotinamide ring thought to enhance hydride transfer. Arguments are made for the relevance of this binding mode to catalysis, and specific consideration is given to how the results extrapolate to provide insight to structure-function relations for the membrane-bound NOX enzymes for which little structural information has been available.
DATABASES
Structural data are available in the PDB database under the accession numbers 3LO8 (wild-type), 5VW4 [Y316S:nicotinamide (P3 21)], 5VW9 [Y316S:nicotinamide (P3 21)], 5VW3 [Y316S:NADP (P3 21)], 5VW8 [Y316S:NADP (P3 21)], 5VW2 [Y316S:NADPH (P3 21)], 5VW5 [Y316A:nicotinamide (P3 21)], 5VW6 [Y316A:NADP (P3 21)], 5VW7 [Y316A:NADPH (P3 21)], 5VWA [Y316F (P3 21)], and 5VWB [Y316F:NADP (P3 21)]. Enzyme Commission number: ferredoxin:NADP reductase - E C1.18.1.2.
未标记
铁氧化还原蛋白：NADP还原酶（FNR）是一种含FAD的酶，在光合作用期间催化电子从铁氧化还原蛋白（Fd）转移至NADP以生成NADPH，因而最为人所知。它也是一个广泛的酶超家族的原型，包括NADPH氧化酶（NOXs），这些酶都催化NAD(P)H与单电子载体之间类似的、依赖FAD的电子转移。在此，我们基于光谱研究以及用烟酰胺、NADP或NADPH浸泡的玉米根FNR Tyr316Ser和Tyr316Ala变体晶体中烟酰胺 - 黄素相互作用的高分辨率（约1.5 Å）晶体学视图，进一步确定了该反应中NAD(P)H ⇌ FAD氢化物转移步骤的机制细节。从FNR晶体复合物获得的光谱与溶液中的光谱相匹配，并且这些复合物揭示了活性位点堆积相互作用以及FAD的共价畸变模式，这意味着活性位点显著压缩，有利于催化作用。此外，各向异性B因子表明，FNR:NADP复合物中烟酰胺C4原子的移动性具有方向性，与烟酰胺环的船型摆动预期方向相匹配，这种摆动被认为可增强氢化物转移。文中阐述了这种结合模式与催化作用的相关性，并特别考虑了这些结果如何外推以深入了解膜结合NOX酶的结构 - 功能关系，目前关于这些酶的结构信息很少。
数据库
结构数据可在PDB数据库中获取，登录号为3LO8（野生型）、5VW4 [Y316S:烟酰胺（P3 21）]、5VW9 [Y316S:烟酰胺（P3 21）]、5VW3 [Y316S:NADP（P3 21）]、5VW8 [Y316S:NADP（P3 21）]、5VW2 [Y316S:NADPH（P3 21）]、5VW5 [Y316A:烟酰胺（P3 21）]、5VW6 [Y316A:NADP（P3 21）]、5VW7 [Y316A:NADPH（P3 21）]、5VWA [Y316F（P3 21）]和5VWB [Y316F:NADP（P3 21）]。酶委员会编号：铁氧化还原蛋白：NADP还原酶 - E C1.18.1.2。
Zotero 插件