Structural insights into a novel functional dimer of Staphylococcus aureus RNase HII
Hang, T., Zhang, X., Wu, M., Wang, C., Ling, S., Xu, L., Gong, Q., Tian, C., Zhang, X., Zang, J.(2018) Biochem Biophys Res Commun 503: 1207-1213
- PubMed: 30005877 
- DOI: https://doi.org/10.1016/j.bbrc.2018.07.026
- Primary Citation of Related Structures:  
5Y9P - PubMed Abstract: 
RNase HII exists ubiquitously in organisms and functions as a monomer in prokaryotes. We determined the crystal structure of Staphylococcus aureus RNase HII (Sa-RNase HII), which displays a novel dimer conformation, with the active site of each monomer covered by the other one. Both small-angle X-ray scattering and gel-filtration analysis confirmed that Sa-RNase HII exists as a homodimer in solution. Enzymatic analysis revealed that the "self-inhibited" dimeric form is catalytically active. Furthermore, continuous-wave electron paramagnetic resonance experiments clarified that the Sa-RNase HII dimer undergoes a large conformational change upon substrate binding, but remains a dimer to catalyze the reaction. Our structural and biochemical studies identified a novel functional dimer of Sa-RNase HII with distinct regulation mechanism for its catalytic activity.
Organizational Affiliation: 
Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Jinzhai Road, Hefei, 230026, China; Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, 230027, China.