Structural basis for single-stranded RNA recognition and cleavage by C3PO.
Translin and translin-associated factor-x are highly conserved in eukaroytes; they can form heteromeric complexes (known as C3POs) and participate in various nucleic acid metabolism pathways. In humans and Drosophila, C3POs cleave the fragmented siRNA passenger strands and facilitate the activation of RNA-induced silencing complex, the effector complex of RNA interference (RNAi). Here, we report three crystal structures of Nanoarchaeum equitans (Ne) C3PO. The apo-NeC3PO structure adopts an open form and unravels a potential substrates entryway for the first time. The NeC3PO:ssRNA and NeC3PO:ssDNA complexes fold like closed football with the substrates captured at the inner cavities. The NeC3PO:ssRNA structure represents the only catalytic form C3PO complex available to date; with mutagenesis and in vitro cleavage assays, the structure provides critical insights into the substrate binding and the two-cation-assisted catalytic mechanisms that are shared by eukaryotic C3POs. The work presented here further advances our understanding on the RNAi pathway.
Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China.
Jing
J
Zhang
Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China.|State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200438, China.
Hehua
H
Liu
State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200438, China.
Qingqing
Q
Yao
Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China.|State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200438, China.
Xiang
X
Yu
Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China.
Yiqing
Y
Chen
State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200438, China.
Ruixue
R
Cui
State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200438, China.
Baixing
B
Wu
State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200438, China.
Lina
L
Zheng
Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China.
Junjun
J
Zuo
Department of Chemistry, Georgia State University, Atlanta, GA 30303, USA huang@gsu.edu.|College of Life Sciences, Sichuan University, Chengdu 610041, China.
Zhen
Z
Huang
State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai 200438, China majb@fudan.edu.cn.
Jinbiao
J
Ma
Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China ganjhh@fudan.edu.cn.
Jianhua
J
Gan
D019843:Archaeal Proteins / Q000737:chemistry* / Q000378:metabolism*; D001665:Binding Sites; D002412:Cations / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D011485:Protein Binding; D012313:RNA / Q000737:chemistry* / Q000378:metabolism; D059367:RNA Cleavage; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D012260:Ribonucleases / Q000737:chemistry / Q000378:metabolism; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
D019843:Archaeal Proteins; D002412:Cations; D016601:RNA-Binding Proteins; D012313:RNA; D012260:Ribonucleases