Structural Basis Of Novel HIV Membrane Fusion Inhibitor

Since HIV was discovered in 1981,it has brought great threat to people’s life safety.So far,there is still no effective vaccine to prevent AIDS.Among many drugs,membrane fusion inhibitors show their unique advantages.HIV gp41 transmembrane protein is one of the main targets of membrane fusion inhibitors.Peptides derived from gp41 CHR can bind to viral NHR and form heterologous 6-HB structure,thus preventing the fusion of viral envelope and target cell membrane.At the same time,with the rapid development of bioinformatics and structural biology,the mechanism of action of many drugs has been gradually revealed.In this study,bioinformatics and structural biology were combined to investigate the structural basis and mechanism of novel HIV membrane fusion inhibitors LP-98 and LP-101.In this study,we first modeled the template peptides P-98 and P-101 of the novel HIV membrane fusion inhibitors LP-98 and LP-101,which were designed and developed in the laboratory in the early stage,through the method of protein homology modeling.After quality assessment,molecular docking with HIV-1 gp41 NHR-derived peptide N44 was performed to predict the possible binding location and mode of action.The molecular docking results show that P-98 and P-101 can be reversely and parallel bound in the hydrophobic gullies formed by N44 trimers and interact with them.At the same time,we found that the binding position of P-98 and P-101 was close to the N terminal of N44,and both of them could interact with the hydrophobic pocket-forming site and the drug-resistant region of T20.Tyr-1 of P-98 and Ile-2 of P-101 played an important role in stabilizing the binding with N44.Based on the above prediction results,we took V38A,V38M and Q40H as examples to explain the formation mechanism of some T20 resistance sites,and analyzed the reasons for the difference in inhibitory activity between LP-98 and LP-101 against some T20 resistance strains by comparing the structures of P-98/N44 and P-101/N44.We believe that P-101 can penetrate into the hydrophobic pocket area of N44 and be closer to it with greater bonding strength.In general or only for T20 resistant areas,P101 has more interactions with N44 than P-98.Therefore,P-101 maybe bind more stably to a target mimic peptide,which is also consistent with the previous functional results of LP-98 and LP-101.Meanwhile,we also analyzed the crystal structure of P101/N44 by the method of structural biology X-ray diffraction,and revealed the real mechanism of P-101.The crystal structure showed that P-101 and N44 did form 6-HB structure,and it proved that the Ile-124 played an important role in promoting the binding of the inhibitor to N44,and there were a lot of interactions between P-101 and N44 in the pocket region and T20 resistance region.Subsequently,we determined theα-helix content and binding stability of lipopeptides LP-101,LP-98,LP-101/N44,LP98/N44 and template peptides P-101,P-98,P-101/N44 and P-98/N44 by circular dichroism,and further demonstrated that compared with LP-98,LP-101 is more stable and can form a tight complex with N44.The template peptide P-101 is also more stable than P-98,and the peptide complex formed with N44 has higher thermal stability,which explains the good antiviral effect of LP-101.Most of the previous studies focused on the function of inhibitors,with few explanations on their mechanism.The purpose of this study was to reveal the inhibition mechanism of novel HIV membrane fusion inhibitors LP-98 and LP-101 by molecular docking and crystal structure diffraction,and to explore the important role of key amino acids in binding with a target mimic peptide.It provides help for researchers to study the mechanism of HIV membrane fusion inhibitors,and also provides new ideas and strategies for the subsequent design and development of broad-spectrum antiviral drugs.