Marcaida Maria J, Kauzlaric Annamaria, Duperrex Alice, Sülzle Jenny, Moncrieffe Martin C, Adebajo Damilola, Manley Suliana, Trono Didier, Dal Peraro Matteo
Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015 Switzerland.
Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015 Switzerland.
iScience. 2020 Nov 18;23(12):101811. doi: 10.1016/j.isci.2020.101811. eCollection 2020 Dec 18.
Members of the DEAD-box helicase family are involved in all fundamental processes of RNA metabolism, and as such, their malfunction is associated with various diseases. Currently, whether and how oligomerization impacts their biochemical and biological functions is not well understood. In this work, we show that DDX21, a human DEAD-box helicase with RNA G-quadruplex resolving activity, is dimeric and that its oligomerization state influences its helicase activity. Solution small-angle X-ray scattering (SAXS) analysis uncovers a flexible multi-domain protein with a central dimerization domain. While the Arg/Gly rich C termini, rather than dimerization, are key to maintaining high affinity for RNA substrates, helicase assays indicate that an intact dimer is essential for both DDX21 ATP-dependent double-stranded RNA unwinding and ATP-independent G-quadruplex remodeling activities. Our results suggest that oligomerization plays a key role in regulating RNA DEAD-box helicase activity.
DEAD-box解旋酶家族成员参与RNA代谢的所有基本过程，因此，它们的功能异常与多种疾病相关。目前，寡聚化是否以及如何影响它们的生化和生物学功能尚不清楚。在这项研究中，我们发现DDX21是一种具有RNA G-四链体解旋活性的人类DEAD-box解旋酶，它以二聚体形式存在，其寡聚化状态影响其解旋酶活性。溶液小角X射线散射（SAXS）分析揭示了一种具有中央二聚化结构域的柔性多结构域蛋白。虽然富含精氨酸/甘氨酸的C末端而非二聚化是维持对RNA底物高亲和力的关键，但解旋酶分析表明，完整的二聚体对于DDX21依赖ATP的双链RNA解旋和不依赖ATP的G-四链体重塑活性都是必不可少的。我们的结果表明，寡聚化在调节RNA DEAD-box解旋酶活性中起关键作用。
