Crystal structure of halophilic dodecin:: A novel, dodecameric flavin binding protein from Halobacterium salinarum
Crystal structure of halophilic dodecin:: A novel, dodecameric flavin binding protein from Halobacterium salinarum
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DOI：
10.1016/s0969-2126(03)00048-0
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发表时间：
2003-04-01
期刊：
影响因子：
5.7
通讯作者：
Oesterhelt, D
中科院分区：
文献类型：
--
作者：
Bieger, B;Essen, LO;Oesterhelt, D
通过反向结构基因组学研究，在盐盐杆菌的蛋白质组中发现了一种新的68个氨基酸长的黄酮类蛋白。该蛋白的1.7埃晶体结构显示出蛋白质亚基的十二聚体中空球形排列。与其他已知的仅结合单体黄素辅助因子的黄素蛋白不同，十二蛋白寡聚物的结构包括六个核黄素二聚体。这些核黄素沿着表面的二聚化是由它们的异alloxazine部分的芳香反平行交错介导的。通过将核黄素二聚体进一步夹在两个对称相关的trp36的吲哚基团之间形成独特的芳香四价体。到目前为止，十二蛋白代表了已知最小的黄素蛋白。根据其结构和在病原菌和土壤真细菌中的广泛分布，推测其具有储存黄素或抵抗自由基或氧胁迫的功能。
A novel, 68 amino acid long flavoprotein called dodecin has been discovered in the proteome of Halobacterium salinarum by inverse structural genomics. The 1.7 Angstrom crystal structure of this protein shows a dodecameric, hollow sphere-like arrangement of the protein subunits. Unlike other known flavoproteins, which bind only monomeric flavin cofactors, the structure of the dodecin oligomer comprises six riboflavin dimers. The dimerization of these riboflavins along the refaces is mediated by aromatic, antiparallel pi staggering of their isoalloxazine moieties. A unique aromatic tetrade is formed by further sandwiching of the riboflavin dimers between the indole groups of two symmetry-related Trp36s. So far, the dodecins represent the smallest known flavoproteins. Based on the structure and the wide spread occurrences in pathogenic and soil eubacteria, a function in flavin storage or protection against radical or oxygenic stress is suggested for the dodecins.