The cDNA for rat selenoprotein P contains 10 TGA codons in the open reading frame.
The cDNA for rat selenoprotein P contains 10 TGA codons in the open reading frame.
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DOI：
10.1016/s0021-9258(18)99185-4
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发表时间：
1991-06
期刊：
影响因子：
--
通讯作者：
K. Hill;R. Lloyd;Jin-Long Yang;R. Read;R. Burk
中科院分区：
文献类型：
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作者：
K. Hill;R. Lloyd;Jin-Long Yang;R. Read;R. Burk
硒蛋白P是最近纯化的血浆蛋白，其特征在于含有7.5 +/-1.0个硒原子/分子作为硒代半胱氨酸。在大鼠维持在一个定义的饮食含有足够的营养量的硒酸盐作为唯一的硒源，超过一半的硒在血浆中占硒蛋白P。它的cDNA已被克隆从大鼠肝脏文库和测序。该序列非常罕见，在TAA终止密码子之前的开放阅读框中含有10个TGA密码子。TGA在其他硒蛋白中指定硒代半胱氨酸，并且包括由TGA密码子中的两个编码的氨基酸的有限肽测序证实它们对应于硒代半胱氨酸。推导出的366个氨基酸的序列是组氨酸和半胱氨酸丰富，并包含其硒代半胱氨酸在末端122个氨基酸中的9个。硒蛋白P的氨基酸序列与其他硒蛋白的氨基酸序列比较，没有发现明显的相似性。硒蛋白P代表了一类新的硒蛋白，并且是第一个在单个多肽链中具有多于1个硒代半胱氨酸的蛋白质。硒蛋白P的一级结构表明，它可能是负责硒的一些抗氧化性能。
Selenoprotein P is a plasma protein recently purified and characterized as containing 7.5 +/- 1.0 selenium atoms/molecule as selenocysteine. In rats maintained on a defined diet containing nutritionally adequate amounts of selenate as the sole selenium source, over half the selenium in plasma is accounted for by selenoprotein P. Its cDNA has been cloned from a rat liver library and sequenced. The sequence is highly unusual, containing 10 TGA codons in its open reading frame prior to the TAA termination codon. TGA designates selenocysteine in other selenoproteins, and limited peptide sequencing that included the amino acids encoded by two of the TGA codons verified that they correspond to selenocysteine. The deduced 366-amino acid sequence is histidine- and cysteine-rich and contains 9 of its selenocysteines in the terminal 122 amino acids. Comparison of the deduced amino acid sequence of selenoprotein P with those of other selenoprotein reveals no significant similarities. Selenoprotein P represents a new class of selenoproteins and is the first protein described with more than 1 selenocysteine in a single polypeptide chain. The primary structure of selenoprotein P suggests that it might be responsible for some of the antioxidant properties of selenium.