Mechanism of coenzyme recognition and binding revealed by crystal structure analysis of ferredoxin-NADP+ reductase complexed with NADP+
Mechanism of coenzyme recognition and binding revealed by crystal structure analysis of ferredoxin-NADP+ reductase complexed with NADP+
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DOI：
10.1016/s0022-2836(02)00388-1
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发表时间：
2002-06-21
影响因子：
5.6
通讯作者：
Medina, M
中科院分区：
文献类型：
--
作者：
Hermoso, JA;Mayoral, T;Medina, M
黄素酶铁氧还蛋白-NADP（+）还原酶（FNR）催化光合作用中NADPH的产生。FNR的三维结构呈现两个不同的结构域，一个用于结合FAD辅基，另一个用于结合NADP（+）。尽管有大量的实验和不同的晶体学方法，关于NADP（+）底物如何与FNR结合以及氢化物离子如何从FAD转移到NADP（+）的许多方面仍然不清楚。通过X射线衍射分析确定了鱼腥藻复合物的结构，共结晶单元的分辨率为2.1埃。由复合物形成诱导的FNR结构扰动产生较窄的空腔，其中NADP（+）的2-磷酸-AMP和焦磷酸部分完美结合。此外，烟酰胺单核苷酸肽部分被置于FAD辅因子附近产生的新口袋中，核糖处于紧密构象。通过共结晶获得的FNR：NADP（+）复合物的晶体结构显示NADP（+）处于不寻常的构象，并且可以被认为是辅酶识别和结合过程中的中间状态。与以前报道的配合物的结构分析和比较，使我们能够假设一种机制，这将允许有效的氢化物转移发生。此外，该结构通过预测新的分子间相互作用，为铁氧还蛋白：FNR：NADP（+）三元复合物的假设形成提供了新的见解，该分子间相互作用仅存在于FNR：NADP（+）复合物形成之后。最后，与广泛的FNR结构家族成员的结构比较也为FNR对NADP（+）/H versns NAD（+）/H表现出的高特异性提供了解释。(C)2002爱思唯尔科技有限公司版权所有。
The flavoenzyme ferredoxin-NADP(+) reductase (FNR) catalyses the production of NADPH in photosynthesis. The three-dimensional structure of FNR presents two distinct domains, one for binding of the FAD prosthetic group and the other for NADP(+) binding. In spite of extensive experiments and different crystallographic approaches, many aspects about how the NADP(+) substrate binds to FNR and how the hydride ion is transferred from FAD to NADP(+) remain unclear. The structure of an complex from Anabaena has been determined by X-ray diffraction analysis of the cocrystallised units to 2.1 Angstrom resolution. Structural perturbation of FNR induced by complex formation produces a narrower cavity in which the 2-phospho-AMP and pyrophosphate portions of the NADP(+) are perfectly bound. In addition, the nicotinamide mononucleotide moiety is placed in a new pocket created near the FAD cofactor with the ribose being in a tight conformation. The crystal structure of this FNR:NADP(+) complex obtained by cocrystallisation displays NADP(+) in an unusual conformation and can be considered as an intermediate state in the process of coenzyme recognition and binding. Structural analysis and comparison with previously reported complexes allow us to postulate a mechanism which would permit efficient hydride transfer to occur. Besides, this structure gives new insights into the postulated formation of the ferredoxin:FNR:NADP(+) ternary complex by prediction of new intermolecular interactions, which could only exist after FNR:NADP(+) complex formation. Finally, structural comparison with the members of the broad FNR structural family also provides an explanation for the high specificity exhibited by FNR for NADP(+)/H versns NAD(+)/H. (C) 2002 Elsevier Science Ltd. All rights reserved.