Water-bridged H-bonds have been observed in many cases of ligand-receptor recognitions. To explore the roles of water bridges in the binding of neonicotinoids with receptors, twenty-four neonicotinoid compounds with nine fragments, including 1 H-1,2,3-triazole, CN, COOMe, CONHNH_2, CONHMe, NO_2,NH_2, NHCOMe and NHCSNH_2 were synthesized and evaluated, of which, compounds with cyano group showed the best activities against Aphis craccivora. Accordingly, the cyano group is the optimal fragment mimicking the water bridge. Two cyano-substituted cis-nitromethylene compounds display good insecticidal activities, whereas the LC_(50) values are lower than those of their corresponding prototypes.Docking study showed that the cyano group acts only as H-bond acceptor, while the water bridge can act as both donor and acceptor. It revealed that the water bridge might be stable in the active site and was not suitable to be replaced by other groups. The findings illustrated that the water bridge is necessary for high insecticidal activities of neonicotinoids, which should be also helpful in better understanding the binding mode of neonicotinoids.
Chengchun ZhuGuanglong LiKeya XiaoXusheng ShaoJiagao ChengZhong Li
Bioactive compounds could form aggregates that influence the bio-interactive processes. In this letter, based on π-π stacking models, quantitative aggregation-activity relationship （QAAR） studies were carried out on a series of sulfonylurea herbicides with good solubility. Four QAAR/QSAR models were constructed, which indicated that the bioactivity may strongly depend on both the characters of the dimeric aggregates and the monomer, The QAAR approach based on dimer-aggregates was also applicable for the highly water-soluble sulfonylurea herbicides that can form π-π stacking interactions. It was expected that the QAAR studies based on molecular aggregation state would be applied to other pesticide systems.
Shuang XiaYue FengJia-Gao ChengHai-Bin LuoZhong LiZheng-Ming Li
