A heterodimer of human 3′-phospho-adenosine-5′-phosphosulphate (PAPS) synthases is a new sulphate activating complex
A heterodimer of human 3′-phospho-adenosine-5′-phosphosulphate (PAPS) synthases is a new sulphate activating complex
复制标题
DOI：
10.1016/j.bbrc.2010.04.039
复制
发表时间：
2010-05-07
影响因子：
3.1
通讯作者：
Mueller, Jonathan W.
中科院分区：
文献类型：
--
作者：
Grum, Daniel;van den Boom, Johannes;Mueller, Jonathan W.
3'-磷酸腺苷-5'-磷酸硫酸合成酶（PAPS）是哺乳动物硫酸盐代谢的基础。这些酶最近与越来越多的人类疾病有关。尽管进行了许多研究，但尚不清楚哺乳动物PAPS合成酶1和2如何相互作用。我们通过下拉试验和福斯特共振能量转移（FRET）测量为这两种酶的异源二聚化提供了第一个证据。二聚体解离/缔合动力学表明，当PAPSS1和-S2在溶液中相遇时，这些异源二聚体就会形成。利用荧光染料IAEDANS标记的蛋白质进行各向异性测量，发现同源二聚体和异源二聚体的亲和力在低纳摩尔范围内，尽管其量子产率低，但由于其大的斯托克斯位移，它非常适合各向异性。在其激酶结构域内，PAPS合成酶异二聚体对5'-磷酸腺苷（APS）的底物抑制与同二聚体相似。由于PAPSS1和-S2的催化效果不同，异源二聚体可能是调节哺乳动物细胞内PAPS合成酶功能的一种方式。(C) 2010爱思唯尔公司版权所有。
3'-Phospho-adenosine-5'-phosphosulphate (PAPS) synthases are fundamental to mammalian sulphate metabolism. These enzymes have recently been linked to a rising number of human diseases. Despite many studies, it is not yet understood how the mammalian PAPS synthases 1 and 2 interact with each other. We provide first evidence for heterodimerisation of these two enzymes by pull-down assays and Forster resonance energy transfer (FRET) measurements. Kinetics of dimer dissociation/association indicates that these heterodimers form as soon as PAPSS1 and -S2 encounter each other in solution. Affinity of the homo- and heterodimers were found to be in the low nanomolar range using anisotropy measurements employing proteins labelled with the fluorescent dye IAEDANS that - in spite of its low quantum yield - is well suited for anisotropy due to its large Stokes shift. Within its kinase domain, the PAPS synthase heterodimer displays similar substrate inhibition by adenosine-5'-phosphosulphate (APS) as the homodimers. Due to divergent catalytic efficacies of PAPSS1 and -S2, the heterodimer might be a way of regulating PAPS synthase function within mammalian cells. (C) 2010 Elsevier Inc. All rights reserved.