Crystal structure of Schizosaccharomyces pombe riboflavin kinase reveals a novel ATP and riboflavin-binding fold
Crystal structure of Schizosaccharomyces pombe riboflavin kinase reveals a novel ATP and riboflavin-binding fold
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DOI：
10.1016/s0022-2836(03)00059-7
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发表时间：
2003-03-07
影响因子：
5.6
通讯作者：
Steinbacher, S
中科院分区：
文献类型：
--
作者：
Bauer, S;Kemter, K;Steinbacher, S
必需的氧化还原辅因子核黄素一磷酸（FMN）和黄素腺嘌呤二核苷酸（FAD）由它们的前体核黄素通过金属依赖性核黄素激酶和FAD合成酶的顺序反应合成。在这里，我们描述了粟酒裂殖酵母核黄素激酶的1.6埃晶体结构。该酶代表了磷酰基转移酶的一个新家族。它是一种单体，包含一个中心β-桶，在一侧由两个C-末端螺旋夹持，显示L样形状。β-桶的相对侧用作底物结合的平台，如与ADP和FMN的复合物所示。与底物游离形式相比，ATP结合位点的形成需要短α-螺旋中的显著重排。ADP的二磷酸部分被由该α-螺旋的部分形成的富含甘氨酸的瓣I覆盖。相反，在结合核黄素时没有观察到显著变化。核糖基侧链可能被一个相当灵活的瓣II覆盖。不寻常的金属结合位点涉及，除了ADP磷酸盐，只有严格保守的Thr 45。这可以解释在体外观察到的对锌的偏好。(C)2003爱思唯尔科技有限公司版权所有。
The essential redox cofactors riboflavin monophosphate (FMN) and flavin adenine dinucleotide (FAD) are synthesised from their precursor, riboflavin, in sequential reactions by the metal-deppndent riboflavin kinase and FAD synthetase. Here, we describe the 1.6 Angstrom crystal structure of the Schizosaccharomyces pombe riboflavin kinase. The enzyme represents a novel family of phosphoryl transferring enzymes. It is a monomer comprising a central beta-barrel clasped on one side by two C-terminal helices that display an L-like shape. The opposite side of the beta-barrel serves as a platform for substrate binding as demonstrated by complexes with ADP and FMN. Formation of the ATP-binding site requires significant rearrangements in a short alpha-helix as compared to the substrate free form. The diphosphate moiety of ADP is covered by the glycine-rich flap I formed from parts of this a-helix. In contrast, no significant changes are observed upon binding of riboflavin. The ribityl side-chain might be covered by a rather flexible flap II. The unusual metal-binding site involves, in addition to the ADP phosphates, only the strictly conserved Thr45. This may explain the preference for zinc observed in vitro. (C) 2003 Elsevier Science Ltd. All rights reserved.