TITLE:
Targeting Divalent Metal Ions at the Active Site of the HIV-1 RNase H Domain: NMR Studies on the Interactions of Divalent Metal Ions with RNase H and Its Inhibitors
AUTHORS:
Jiangli Yan, Haihong Wu, Tiffany Tom, Oleg Brodsky, Karen Maegley
KEYWORDS:
Metal Chelation, HIV-1, Reverse Transcriptase, RNase H, NMR Spectroscopy
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.2 No.6,
October
11,
2011
ABSTRACT: HIV-1 reverse transcriptase (RT) RNase H (HIV-RH) is a key target of anti-AIDS drugs. Metal-chelating compounds are an important class of chemicals in pharmacological drug discovery, especially in relation to HIV-RT and the highly-related HIV-integrase. The correlation between the metal-chelating properties and enzyme activities of the metal chelators is always of high scientific interest, as an understanding of this may accelerate the rational optimization of this class of inhibitors. Our NMR data show that Mg2+ and Ca2+ bind specifically to the active site of the RNase H domain and two Mg2+ ions sequentially bind one molecule of RNase H. We also demonstrate here, using saturated and unsaturated tricyclic N-hydroxypyridones designed to block the active site, that the primary binding sites and affinities of divalent metal ions are correlated with the structures of the chelating motifs. Chemical shift perturbation studies of protein/metal-ion/compound ternary complexes also indicate that divalent metal ions play important roles for the specific interaction of the compounds with the RNase H active site.