Structure-based cleavage mechanism of Thermus thermophilus Argonaute DNA guide strand-mediated DNA target cleavage.
Sheng, G., Zhao, H., Wang, J., Rao, Y., Tian, W., Swarts, D.C., van der Oost, J., Patel, D.J., Wang, Y.(2014) Proc Natl Acad Sci U S A 111: 652-657
- PubMed: 24374628 
- DOI: https://doi.org/10.1073/pnas.1321032111
- Primary Citation of Related Structures:  
4KPY, 4N41, 4N47, 4N76, 4NCA, 4NCB - PubMed Abstract: 
We report on crystal structures of ternary Thermus thermophilus Argonaute (TtAgo) complexes with 5'-phosphorylated guide DNA and a series of DNA targets. These ternary complex structures of cleavage-incompatible, cleavage-compatible, and postcleavage states solved at improved resolution up to 2.2 Å have provided molecular insights into the orchestrated positioning of catalytic residues, a pair of Mg(2+) cations, and the putative water nucleophile positioned for in-line attack on the cleavable phosphate for TtAgo-mediated target cleavage by a RNase H-type mechanism. In addition, these ternary complex structures have provided insights into protein and DNA conformational changes that facilitate transition between cleavage-incompatible and cleavage-compatible states, including the role of a Glu finger in generating a cleavage-competent catalytic Asp-Glu-Asp-Asp tetrad. Following cleavage, the seed segment forms a stable duplex with the complementary segment of the target strand.
Organizational Affiliation: 
Laboratory of Non-Coding RNA, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.