The Interaction Of HIV-1 Nucleocapsid Protein NCp7 With G-quadruplex And Ruthenium Complexes

Antiretroviral drugs used to treat human immunodeficiency virus type 1(HIV-1)infection have prolonged the survival of millions of HIV-1 carriers.However,drug resistance and side effects have brought significant challenges to their clinical application.New anti-HIV-1 drugs are needed to maintain the gains achieved in HIV care.The nucleocapsid protein of HIV-1(NCp7)plays a significant role in the viral life cycle through its highly conserved zinc-finger structure.Inhibitors of NCp7 inhibit the replication and infection of HIV-1 and are unlikely to be overcome by evolved drug resistance.These two characteristics make NCp7 a powerful target for anti-HIV-1 drugs,but NCp7 inhibitors have not been used in clinical settings due to their low target activity and high rate of adverse effects.Next-generation inhibitors of NCp7 are urgently needed to overcome these limitations.The rise of chemotherapy and the clinical success of cisplatin have ushered in a new field of metal-based drug research and development.In the search for nonplatinum anticancer drugs,ruthenium compounds have emerged as one of the most promising metallodrugs with low toxicity and effective anticancer and antitumor metastatic activity.Mechanism studies have shown that protein is the main target for ruthenium compounds in vivo.Coordination chemistry studies indicate the sulfhydryl group in the zinc-finger region of NCp7 is a potential ruthenium target,suggesting ruthenium complexes may be inhibitors of NCp7.Bioinformatics studies have proved that guanine-rich sequences in the HIV-1 genome form stable G-quadruplex structures under physiological conditions.The stability of the G-quadruplex structure regulates the reverse transcription of HIV-1.Ligands that stabilize the G-quadruplex structure inhibit reverse transcription.Therefore,the G-quadruplex represents an anti-HIV-1 target as powerful as NCp7.Interestingly,recent studies have shown that NCp7 has a strong affinity for G-quadruplex and may promote HIV-1 reverse transcription by destroying the stable G-quadruplex structure.This finding inspired us to inhibit HIV-1 by double targeting(NCp7/G-quadruplex).However,the mechanism by which NCp7 destroys the stable G-quadruplex structure remains unclear.We sought to provide a molecular theoretical basis for the development of anti-HIV-1 drugs and describe the mechanism of NCp7 with G-quadruplex or ruthenium complexes in detail.The main contents and results are as follows:1.We studied the mechanism of interaction between NCp7 and heterozygous G-quadruplex(duplex/quadruplex hybrid structure).The duplex structure in the stem-loop region of LTR-? is the preferential binding site of NCp7,facilitated by ?-? stacking between the aromatic residues of NCp7(Phe16 and Trp37)and bases G5 and G6 of the G-quadruplex structure.NCp7 binding twists the top G-tetrad,weakens hydrogen bonding,and causes K+ejection,disrupting the G-quadruplex structure.2.We explored the possibility of ruthenium complexes as NCp7 inhibitors.The ruthenium complexes covalently bound to the sulfhydryl group of cysteine residues of NCp7,expelled its zinc ions,and then destroyed the highly conserved zinc-finger structure,disrupting NCp7 binding with the nucleic acid.3.We explored the ruthenium complex structure-activity and interaction with NCp7 and found that the interaction mode between ruthenium compounds and protein can be altered by changing the ligands.In conclusion,this work elucidates the structural mechanism of NCp7 with hybrid G-quadruplex,which contributes to the development of anti-HIV-1 drugs targeting NCp7/G-quadruplex and providing a new perspective on how NCp7 promotes HIV-1 reverse transcription.The ruthenium complex inhibits the biological function of NCp7,and this function can be enhanced by changing the ligand,offering a molecular basis for developing effective NCp7 inhibitors.