Human mitochondrial AAA+ ATPase SKD3/CLPB assembles into nucleotide-stabilized dodecamers.
Human mitochondrial AAA+ ATPase SKD3/CLPB assembles into nucleotide-stabilized dodecamers.
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人线粒体 AAA+ ATP 酶 SKD3/CLPB 组装成核苷酸稳定的十二聚体。
DOI：
10.1016/j.bbrc.2022.02.101
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发表时间：
2022-04-30
影响因子：
3.1
通讯作者：
Zolkiewski M
中科院分区：
文献类型：
--
作者：
Spaulding Z;Thevarajan I;Schrag LG;Zubcevic L;Zolkiewska A;Zolkiewski M
SKD 3，也称为人CLPB，属于与各种活性相关的ATP酶的AAA+家族。SKD 3/CLPB基因突变导致VII型3-甲基戊烯二酸尿症和先天性中性粒细胞减少症。SKD 3在急性髓性白血病中上调，在那里它有助于抗癌药物耐药性。SKD 3存在于线粒体膜间隙，在那里它形成ATP依赖性高分子量复合物，但其生物学功能和与临床表型的机制联系目前尚不清楚。使用沉降平衡和动态光散射，我们表明，SKD 3是单体在低蛋白浓度的核苷酸的情况下，但它在较高的蛋白浓度或在腺嘌呤核苷酸的存在下形成寡聚体。核苷酸结合的SKD 3的表观分子量与12个单体的自缔合一致。图像类分析和平均从负染色电子显微镜（EM）的SKD 3在ATP结合状态可视化的圆柱形颗粒与开放的中央通道沿着圆柱轴。EM可视化颗粒的尺寸表明SKD 3十二聚体是由两个六聚体环缔合形成的。虽然在AAA+ ATP酶中经常观察到六聚体结构，但在SKD 3中发现的双六聚体三明治在该蛋白质家族中似乎并不常见。SKD 3的非典型结构的功能意义仍有待确定。
SKD3, also known as human CLPB, belongs to the AAA+ family of ATPases associated with various activities. Mutations in the SKD3/CLPB gene cause 3-methylglutaconic aciduria type VII and congenital neutropenia. SKD3 is upregulated in acute myeloid leukemia, where it contributes to anti-cancer drug resistance. SKD3 resides in the mitochondrial intermembrane space, where it forms ATP-dependent high-molecular weight complexes, but its biological function and mechanistic links to the clinical phenotypes are currently unknown. Using sedimentation equilibrium and dynamic light scattering, we show that SKD3 is monomeric at low protein concentration in the absence of nucleotides, but it forms oligomers at higher protein concentration or in the presence of adenine nucleotides. The apparent molecular weight of the nucleotide-bound SKD3 is consistent with self-association of 12 monomers. Image-class analysis and averaging from negative-stain electron microscopy (EM) of SKD3 in the ATP-bound state visualized cylinder-shaped particles with an open central channel along the cylinder axis. The dimensions of the EM-visualized particle suggest that the SKD3 dodecamer is formed by association of two hexameric rings. While hexameric structure has been often observed among AAA+ ATPases, a double-hexamer sandwich found for SKD3 appears uncommon within this protein family. A functional significance of the non-canonical structure of SKD3 remains to be determined.
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影响因子：
3.7
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