The CXXC motif: Imperatives for the formation of native disulfide bonds in the cell
The CXXC motif: Imperatives for the formation of native disulfide bonds in the cell
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DOI：
10.1002/j.1460-2075.1996.tb00626.x
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发表时间：
1996-06-03
期刊：
影响因子：
11.4
通讯作者：
Raines, RT
中科院分区：
文献类型：
--
作者：
Chivers, PT;Laboissiere, MCA;Raines, RT
细胞蛋白质中天然二硫键的快速形成是有效利用细胞资源所必需的。该过程在体外由蛋白二硫异构酶（PDI）催化，PDI1基因对酿酒酵母的生存能力至关重要。PDI是硫氧还蛋白（Trx）家族的成员，其活性位点基序为CXXC。PDI包含两个Trx结构域以及两个与Trx家族无关的结构域。我们发现编码大肠杆菌Trx的基因不能补体酿酒杆菌的PDI1零突变体。然而，如果Trx突变为具有高还原电位二硫键的CXXC基序和低pK的巯基，则Trx可以取代PDI (a)。因此，酶硫酸盐对于细胞内形成天然二硫键既是必要的又是充分的。
The rapid formation of native disulfide bonds in cellular proteins is necessary for the efficient use of cellular resources. This process is catalyzed in vitro by protein disulfide isomerase (PDI), with the PDI1 gene being essential for the viability of Saccharomyces cerevisiae. PDI is a member of the thioredoxin (Trx) family of proteins, which have the active-site motif CXXC. PDI contains two Trx domains as well as two domains unrelated to the Trx family. We find that the gene encoding Escherichia coli Trx is unable to complement PDI1 null mutants of S.cerevisiae. Yet, Trx can replace PDI if it is mutated to have a CXXC motif with a disulfide bond of high reduction potential and a thiol group of low pK(a). Thus, an enzymic thiolate is both necessary and sufficient for the formation of native disulfide bonds in the cell.