Structural and biochemical characterization of fructose-1,6/sedoheptulose-1,7-bisphosphatase from the cyanobacterium Synechocystis strain 6803
Structural and biochemical characterization of fructose-1,6/sedoheptulose-1,7-bisphosphatase from the cyanobacterium Synechocystis strain 6803
复制标题
蓝藻集胞藻菌株 6803 果糖-1,6/景天庚酮糖-1,7-双磷酸酶的结构和生化特征
DOI：
10.1111/febs.12657
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发表时间：
2014-02-01
期刊：
影响因子：
5.4
通讯作者：
Hu, Xiaopeng
中科院分区：
文献类型：
--
作者：
Feng, Lingling;Sun, Yao;Hu, Xiaopeng
蓝藻果糖-1，6/景天庚酮糖-1，7-二磷酸酶（cy-FBP/SBPase）在糖异生和光合碳还原途径中发挥着至关重要的作用，因此是抑制有害蓝藻水华的潜在酶靶点。在这里，我们描述了与AMP和果糖-1，6-二磷酸（FBP）的复合物中的cy-FBP/SBYP的晶体结构。变构抑制剂AMP和底物FBP在与cy-FBP/SBYP复合时表现出不寻常的结合模式。结合模式分析表明，AMP结合到四聚体中心的上/下亚基对C1 C4和C2 C3的界面附近的变构位点，而FBP结合到水平亚基对C1 C2或C3 C4之间的界面对面。我们确定了一系列的残基，重要的FBP和AMP的结合，并建议Cys 75和Cys 99之间的二硫键的形成。进一步的分析表明，cy-FBP/SBR 2可能通过配体结合和酶复合物结构的改变来调节。配体与cy-FBP/SBPase之间的相互作用与其他FBPase家族成员的配体结合结构不同，从而为cy-FBP/SBPase的结构和催化的分子机制提供了新的见解。我们的研究提供了深入了解这种酶家族的演变，并可能有助于设计旨在防止有毒蓝藻水华的抑制剂。
Cyanobacterial fructose-1,6/sedoheptulose-1,7-bisphosphatase (cy-FBP/SBPase) plays a vital role in gluconeogenesis and in the photosynthetic carbon reduction pathway, and is thus a potential enzymatic target for inhibition of harmful cyanobacterial blooms. Here, we describe the crystal structure of cy-FBP/SBPase in complex with AMP and fructose-1,6-bisphosphate (FBP). The allosteric inhibitor AMP and the substrate FBP exhibit an unusual binding mode when in complex with cy-FBP/SBPase. Binding mode analysis suggested that AMP bound to the allosteric sites near the interface across the up/down subunit pairs C1C4 and C2C3 in the center of the tetramer, while FBP binds opposite to the interface between the horizontal subunit pairs C1C2 or C3C4. We identified a series of residues important for FBP and AMP binding, and suggest formation of a disulfide linkage between Cys75 and Cys99. Further analysis indicates that cy-FBP/SBPase may be regulated through ligand binding and alteration of the structure of the enzyme complex. The interactions between ligands and cy-FBP/SBPase are different from those of ligand-bound structures of other FBPase family members, and thus provide new insight into the molecular mechanisms of structure and catalysis of cy-FBP/SBPase. Our studies provide insight into the evolution of this enzyme family, and may help in the design of inhibitors aimed at preventing toxic cyanobacterial blooms.