HIV-1 gains entry into target cells by sequentially interacting with cellular receptors and co-receptors. Both the receptor and co-receptor are recognized by HIV-1 envelope protein gpl20, which plays a key role in the entry process of HIV-1 into cells. The development of new inhibitors is essential since the viral enzyme reverse transcriptase （RT） is one of the first targets of antiretroviral therapy. It has been reported that a variety of natural plants, such as Artemisia rupestris L., have anti-viral pharmacological activity, and they might be the potential inhibitors of RT or V3 loop of gpl20 against HIV-1. RIQRGPGRAFVT1GK （R15K）, the relatively conserved region of V3 loop, can be used for binding research. In this work, we analyzed the interactions between different extracts from Artemisia rupestris L. and R15K by affinity capillary electrophoresis （ACE）. Moreover, we analyzed the interactions between different extracts from Artemisia rupestris L. and RT by capillary zone electrophoresis （CZE）. Our data showed that the chloroform extract ofArtemisia rupestris L. was active among the different plant extracts, which was consistent with previous studies. Taken together, our study provided a rapid screening method to seek anti-HIV ingredients in natural plants＇ extracts.
CC chemokine receptor 4（CCR4） is a G-protein-coupled receptor which plays a pivotal role in allergic inflammation. In the present study, three extracellular loops（EL1-3） of CCR4 were synthesized, and the interactions between the extracellular loops and compound S009 were investigated using capillary zone electrophoresis（CZE）. Both qualitative and quantitative characterizations of the compound-peptide binding were carried out. The experimental data indicated that compound S009 exhibited interactions with EL3, and a binding constant of（12.5±0.19）×10^4 M^-1 was determined using the Scatchard plot. Our study identified the specific domains of CCR4 that could be targeted by small molecules and provided insights for the discovery of novel CCR4 antagonists.
V3 loop of HIV-1 envelop protein gp120 plays a pivotal role in the entry process of HIV-1 into target cells. R15K, the relatively conserved region of V3 loop, can be used in binding studies instead of recombinant gp120 molecule. Polyanionic compounds, such as carrageenan, possess antiviral activity through disrupting gp120-CD4 interaction, and chemical modifications have been performed to improve such activity. In this work, we, for the first time, analyzed the interactions between carrageenan or its degradation and R15K by affinity capillary electrophoresis （ACE）. Our results revealed that depolymerized carrageenan rather than carrageenan could bind to R15K. The binding constant of depolymerized carrageenan was （2.94±0.57）× 10^6 mol/L. Our finding indicated that the depolymerized carrageenan could be R15K antagonist, and it might inhibit the infection of HIV-1 through the entry process.
