Crystal structure and functional studies of an unusual L-cysteine desulfurase from Archaeoglobus fulgidus.
Crystal structure and functional studies of an unusual L-cysteine desulfurase from Archaeoglobus fulgidus.
复制标题
来自古生球菌的一种不寻常的 L-半胱氨酸脱硫酶的晶体结构和功能研究。
作者：
Y. Yamanaka;Laura Zeppieri;Y. Nicolet;Elodie N. Marinoni;J. S. de Oliveira;M. Odaka;D. Dean;J. Fontecilla
L-半胱氨酸脱硫酶IscS和支架IscU蛋白普遍参与Fe/S簇的合成。闪烁古生球菌（Af）基因组编码与来自其它生物体的IscS和IscU具有高度一级结构相似性的蛋白质。然而，AfIscS是不寻常的，因为它缺乏活性位点赖氨酸残基，该活性位点赖氨酸残基通常与磷酸吡哆醛（PLP）形成内部席夫碱并在催化期间充当碱。我们分离的重组AfIscS含有磷酸吡哆胺（PMP），而不是预期的PLP，缺乏脱硫酶活性。我们已经解决了它的结构，以1.43 μ m的分辨率，并发现PMP结合在非共价键的酶的PLP网站，并显示出显着的障碍。然而，先前报道的重组Af（IscU-D35 A-IscS）（2）的结构在AfIscU内含有体内产生的[Fe（2）S（2）]物质，并且产生了关于其硫化物如何产生的问题。在这里，我们报告说，加入PLP的AfIscS产生的酶，显示在体外L-半胱氨酸脱硫酶活性介导的合成一个稳定的holo Af（IscU-D35 A-IscS）复合物。
L-Cysteine desulfurase IscS and scaffold IscU proteins are universally involved in Fe/S cluster synthesis. The Archaeoglobus fulgidus (Af) genome encodes proteins having a high degree of primary structure similarity to IscS and IscU from other organisms. However, AfIscS is unusual because it lacks the active site lysine residue that normally forms an internal Schiff base with pyridoxal-phosphate (PLP) and serves as a base during catalysis. Our as-isolated recombinant AfIscS contains pyridoxamine phosphate (PMP) instead of the expected PLP and lacks desulfurase activity. We have solved its structure to 1.43 Å resolution and found that PMP binds non-covalently at the PLP site of the enzyme and displays significant disorder. However, the previously reported structure of recombinant Af(IscU-D35A-IscS)(2) contains an in vivo generated [Fe(2)S(2)] species within AfIscU and the question arises as to how its sulfides were generated. Here, we report that adding PLP to AfIscS produces an enzyme that displays in vitro L-cysteine desulfurase activity mediating the synthesis of a stable holo Af(IscU-D35A-IscS) complex.
影响因子：
2.9
作者：
DAILEY, HA;FINNEGAN, MG;JOHNSON, MK
通讯作者：
JOHNSON, MK
影响因子：
56.9
作者：
Beinert, H;Holm, RH;Munck, E
通讯作者：
Munck, E