Characterization of iron binding in IscA, an ancient iron-sulphur cluster assembly protein
Characterization of iron binding in IscA, an ancient iron-sulphur cluster assembly protein
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DOI：
10.1042/bj20031702
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发表时间：
2004-04-15
影响因子：
4.1
通讯作者：
Clark, RJ
中科院分区：
文献类型：
--
作者：
Ding, HG;Clark, RJ
铁硫簇合物是生物中最常见的氧化还原中心之一。至少有六种蛋白质（IscS、IscU、IscA、HscB、HscA和铁氧还蛋白）已被鉴定为细菌中铁硫蛋白生物合成所必需的。已经表明，IscS是为铁-硫簇提供硫的半胱氨酸蛋白酶，并且IscU是IscS介导的铁-硫簇组装的支架。然而，铁硫簇合物的铁供体仍然难以捉摸。在这里，我们表明，IscA是一种铁结合蛋白，具有3.0 × 10（19）M-1的表观铁结合常数，并且在体外IscS和L-半胱氨酸存在下，负载铁的IscA可以为IscU中瞬时铁硫簇的组装提供铁。结果表明，IscA能够募集细胞内铁，并将铁传递给蛋白质中的铁硫簇。
Iron-sulphur clusters are one of the most common types of redox centre in biology. At least six proteins (IscS, IscU, IscA, HscB, HscA and ferredoxin) have been identified as being essential for the biogenesis of iron-sulphur proteins in bacteria. It has been shown that IscS is a cysteme desulphurase that provides sulphur for iron-sulphur clusters, and that IscU is a scaffold for the IscS-mediated assembly of iron-sulphur clusters. The iron donor for iron-sulphur clusters, however, remains elusive. Here we show that IscA is an iron binding protein with an apparent iron association constant of 3.0 x 10(19) M-1, and that iron-loaded IscA can provide iron for the assembly of transient iron-sulphur clusters in IscU in the presence of IscS and L-Cysteine in vitro. The results suggest that IscA is capable of recruiting intracellular iron and delivering iron for iron-sulphur clusters in proteins.