Crystal structures of RbsD leading to the identification of cytoplasmic sugar-binding proteins with a novel folding architecture
Crystal structures of RbsD leading to the identification of cytoplasmic sugar-binding proteins with a novel folding architecture
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DOI：
10.1074/jbc.m304523200
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发表时间：
2003-07-25
影响因子：
4.8
通讯作者：
Oh, BH
中科院分区：
文献类型：
--
作者：
Kim, MS;Shin, J;Oh, BH
RbsD是参与核糖主动转运的rbs操纵子的六种基因产物中唯一一种生化功能未知的蛋白质。FucU是RbsD在细菌和人类中的一种保守蛋白，也是L-岩藻糖调节子的七种基因产物中唯一功能未知的蛋白。在这里，我们报告的晶体结构的枯草芽孢杆菌RbsD，这揭示了一种新的十聚体环形组装的蛋白质。对RbsD的核磁共振和其他研究表明，蛋白质的亚基间裂缝结合特定形式的D-核糖，但它对糖没有酶活性。同样，FucU结合L-岩藻糖，但缺乏对这种糖的酶活性。我们得出结论，RbsD和FucU是细胞质糖结合蛋白，一类新的蛋白质，其功能作用可能在于帮助流入的糖底物。
RbsD is the only protein whose biochemical function is unknown among the six gene products of the rbs operon involved in the active transport of ribose. FucU, a paralogue of RbsD conserved from bacteria to human, is also the only protein whose function is unknown among the seven gene products of the L-fucose regulon. Here we report the crystal structures of Bacillus subtilis RbsD, which reveals a novel decameric toroidal assembly of the protein. Nuclear magnetic resonance and other studies on RbsD reveal that the intersubunit cleft of the protein binds specific forms of D-ribose, but it does not have an enzyme activity toward the sugar. Likewise, FucU binds L-fucose but lacks an enzyme activity toward this sugar. We conclude that RbsD and FucU are cytoplasmic sugar-binding proteins, a novel class of proteins whose functional role may lie in helping influx of the sugar substrates.