期刊
NATURE CHEMICAL BIOLOGY
卷 13, 期 5, 页码 508-+出版社
NATURE PUBLISHING GROUP
DOI: 10.1038/NCHEMBIO.2333
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资金
- CRUK [A18604]
- Biotechnology and Biological Sciences Research Council [BB/P001491/1, B17092, BB/E001777/1] Funding Source: researchfish
- Cancer Research UK [11722, 18604] Funding Source: researchfish
- Engineering and Physical Sciences Research Council [EP/J017094/1] Funding Source: researchfish
The TS ribozyme (originally called twister sister) is a catalytic RNA. We present a crystal structure of the ribozyme in a pre-reactive conformation. Two co-axial helical stacks are organized by a three-way junction and two tertiary contacts. Five divalent metal ions are directly coordinated to RNA ligands, making important contributions to the RNA architecture. The scissile phosphate lies in a quasihelical loop region that is organized by a network of hydrogen bonding. A divalent metal ion is directly bound to the nucleobase 5' to the scissile phosphate, with an inner-sphere water molecule positioned to interact with the O2' nucleophile. The rate of ribozyme cleavage correlated in a log-linear manner with divalent metal ion pK(a), consistent with proton transfer in the transition state, and we propose that the bound metal ion is a likely general base for the cleavage reaction. Our data indicate that the TS ribozyme functions predominantly as a metalloenzyme.
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