Self William T, Pierce Renee, Stadtman T C
Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892-8012, USA.
IUBMB Life. 2004 Aug;56(8):501-7. doi: 10.1080/15216540400010818.
The activation and incorporation of selenium into selenocysteine containing selenoproteins has been well established in an Escherichia coli model system but there is little specific information concerning the transport and intracellular trafficking of selenium in biological systems in general. A selenium transport role is a possible function of a novel 42 kDa selenium-binding protein that recently was purified from Methanococcus vannielii. The gene encoding a monomer of this protein (Sbp) has been cloned, sequenced and heterologously expressed in E. coli. The 8.8 kDa gene product contains 81 amino acids. The recombinant Sbp (rSbp) protein was shown to bind selenium from added selenite. The bound selenium appeared predominantly in dimeric and tetrameric forms of the protein. The gene encoding Sbp occurs in an operon that contains a carbonic anhydrase gene and selenocysteine-containing formate dehydrogenase genes, suggesting possible roles in selenium-dependent formate metabolism.
在大肠杆菌模型系统中，硒的激活以及将其掺入含硒代半胱氨酸的硒蛋白已得到充分证实，但总体而言，关于生物系统中硒的转运和细胞内运输的具体信息却很少。一种新的42 kDa硒结合蛋白可能具有硒转运功能，该蛋白最近从万氏甲烷球菌中纯化得到。编码该蛋白单体（Sbp）的基因已被克隆、测序并在大肠杆菌中进行了异源表达。这个8.8 kDa的基因产物包含81个氨基酸。重组Sbp（rSbp）蛋白显示能从添加的亚硒酸盐中结合硒。结合的硒主要以该蛋白的二聚体和四聚体形式存在。编码Sbp的基因存在于一个操纵子中，该操纵子包含一个碳酸酐酶基因和含硒代半胱氨酸的甲酸脱氢酶基因，这表明其在硒依赖性甲酸代谢中可能发挥作用。
