Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “HIV Reverse Transcriptase”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 433 records · Page 24Linked to original sources
PubMed2006

Site-directed mutagenesis in the fingers subdomain of HIV-1 reverse transcriptase reveals a specific role for the beta3-beta4 hairpin loop in dNTP selection.

HIV-1 reverse transcriptase shares the key features of high fidelity polymerases, such as a closed architecture of the active site, but displays a level of fidelity that is intermediate to that of high fidelity, replicative polymerases and low fidelity translesion synthesis (TLS) polymerases. The beta3-beta4 loop of the HIV-1 RT fingers subdomain makes transient contacts with the dNTP and template base. To investigate the role of active site architecture in HIV-1 RT fidelity, we truncated the beta3-beta4 loop, eliminating contact between Lys65 and the gamma-phosphate of dNTP. The mutant, in a manner reminiscent of TLS polymerases, was only able to incorporate a nucleotide that was capable of base-pairing with the template nucleotide, but not a nucleotide shape-analog incapable of Watson-Crick hydrogen bonding. Unexpectedly, however, the deletion mutant differed from the TLS polymerases in that it displayed an increased fidelity. The increased fidelity was associated with reduced dNTP binding affinity as measured using the dead end complex formation. In an effort to delineate the specific amino acid residue in the deleted segment responsible for this phenotype, we examined the K65 residue. Two substitution mutants, K65R and K65A were studied. The K65A mutant behaved similarly to the deletion mutant displaying dependence on Watson-Crick hydrogen bonding, increased fidelity and reduced dNTP-binding, while the K65R was more akin to wild-type enzyme. These results underscore the key role of the K65 residue in the phenotype observed in the deletion mutant. Based on the well-known electrostatic interaction between K65 and the gamma-phosphate moiety of incoming dNTP substrate in the ternary complex structure of HIV-1 RT, we conclude that non-discriminatory interactions between beta3-beta4 loop and the dNTP in wild-type HIV-1 RT help lower dNTP selectivity. Our results show that the fidelity of dNTP insertion is influenced by protein interactions with the triphosphate moiety.

Alanine↗
PubMed2001

Conformational analysis of nevirapine, a non-nucleoside HIV-1 reverse transcriptase inhibitor, based on quantum mechanical calculations.

The structure and the conformational behavior of the HIV-1 reverse transcriptase inhibitor, 11-cyclopropyl-5,11dihydro-4-methyl-6H-dipyrido[3,2-b2',3'-e][1,4]diazepin-6-one (nevirapine), is investigated by semiempirical (MNDO, AMI and PM3) method, ab initio at the HF/3-21G and HF/6-31G** levels and density functional theory at the B3LYP/6-31G** level. The fully optimized structure and rotational potential of the nitrogen and carbon bond in the cyclopropyl ring were examined in detail. A similar geometrical minimum is obtained from all methods which shows an almost identical structure to the geometry of the molecule in the complex structure with HIV-1 reverse transcriptase. To get some information on the structure in solution, NMR chemical shift calculations were also performed by a density functional theory at the B3LYP/6-31G** level, using GIAO approximation. The calculated 1H-NMR and 13C-NMR spectra for the energy minimum geometry agree well with the experimental results, which indicated that the geometry of nevirapine in solution is very similar to that of the molecule in the inhibition complex. Furthermore, the obtained results are compared to the conformational studies of other non-nucleoside reverse transcriptase inhibitors and reveal a common agreement of the non-nucleoside reverse transcriptase inhibitors. The specific butterfly-like shape and conformational flexibility within the side chain of the non-nucleoside reverse transcriptase inhibitors play an important role inducing conformational change of HIV-1 reverse transcriptase structure and are essential for the association at the inhibition pocket.

Anti-HIV Agents↗
PubMed2000

First demonstration of an inhibitory activity of milk proteins against human immunodeficiency virus-1 reverse transcriptase and the effect of succinylation.

A variety of milk proteins including lactoferrin, angiogenin-1, alpha-lactalbumin, beta-lactoglobulin, lactoperoxidase, casein and the novel whey proteins lactogenin and glycolactin were tested for inhibitory activity toward human immunodeficiency virus-1 reverse transcriptase (HIV-1 RT), alpha-glucosidase, beta-glucosidase and beta-glucuronidase. Lactoferrin exerted the most potent inhibitory action with an IC50 of about 6 microM. Lactoperoxidase, lactogenin, angiogenin-1 and glycolactin inhibited HIV-1 RT activity with decreasing potencies. Beta-lactoglobulin, alpha-lactalbumin and casein displayed little or no inhibitory effect. Succinylation with succinic anhydride augmented the inhibitory effect of glycolactin, beta-lactoglobulin, alpha-lactalbumin, casein and human lactoferrin. The inhibitory effect of the various milk proteins on the activities of alpha-glucosidase, beta-glucosidase and beta-glucuronidase was meager. Succinylation tended to increase the alpha-glucosidase-inhibitory effect of milk proteins but neither their beta-glucosidase-inhibitory nor beta-glucuronidase-inhibitory effect was affected.

Animals↗
PubMed1992

Epitope mapping of HIV-1 reverse transcriptase with monoclonal antibodies that inhibit polymerase and RNase H activities.

Lysates from E. coli expressing HIV-1 reverse transcriptase (RT) as a TrpE fusion protein were used for immunization of BALB/c mice. Twenty hybridomas producing monoclonal antibodies (MAbs) recognizing the RT part of the TrpE-RT fusion protein by Western blot analysis were isolated. Of these, 18 were reactive in immunofluorescence assays when tested on HIV-infected cells. Twelve MAbs were reactive with both the p66 and p51 fragments of RT, while 6 of the MAbs were reactive only with the p66 band, indicating specificity for the C-terminal (RNase H) region of RT. Mapping of the monoclonal antibody binding sites was performed using deletion and insertion mutants of recombinant RT. The antibodies bound to five distinct regions within amino acid sequences 190-560 of RT. In order to map functionally important regions of the RT molecule, the MAbs were tested for their ability to interfere with the polymerase and RNase H activities of the polypeptide. MAbs binding to two different epitopes in the polymerase domain were found to inhibit the polymerase activity. Of these, three MAbs also inhibited the RNase H activity. Two MAbs binding to the same epitope in the RNase H region inhibited RNase H activity and further mediated an effect on the polymerase activity.

Amino Acid Sequence↗
PubMed2002

Quantitative structure-activity relationship study of 2-arylsulfonyl-6-substituted benzonitriles as non-nucleoside reverse transcriptase inhibitors of HIV-1.

The reverse transcriptase inhibition of HIV-1, the most common form of HIV, by non-nucleoside 2-arylsulfonyl-6-substituted benzonitriles is analysed through Fujita-Ban and Hansch approaches. The analyses have helped to ascertain the role of different substituents in explaining the observed inhibitory actions of these compounds. From both approaches it appeared that SO2 instead of SO or S at X; and NH2 instead of F at Y (see Figure 1) are advantageous to improving the activity of a compound against HIV-1. This in turn leads to the suggestion that the 2-arylsulfonyl-6-aminobenzonitrile scaffold is the only appropriate structural entity that may further result into potential compounds. Further, the compounds having a OMe substituent at the orthoposition, the bulkier substituents at meta-positions and "no" substituent at para-position of 2-arylsulfonyl moiety are beneficial in raising the activity. The two quantitative structure-activity relationship (QSAR) analyses, differing in parametric approach, therefore, provided the grounds for rationalizing the substituent selection in designing more potent compounds of the series.

Anti-HIV Agents↗
PubMed1996

Rational approaches to resistance: nucleoside analogues.

AIM: To review knowledge of drug-resistance patterns to nucleoside HIV reverse transcriptase inhibitors and how this can be used to advantage in patient management. PATTERNS OF RESISTANCE: The speed of emergence of HIV-1 drug resistance is dependent on host, viral and drug factors. Resistance to zidovudine develops over months to years, and is associated with mutations in HIV reverse transcriptase at positions 41, 67, 70, 215 and 219. Reductions in susceptibility to didanosine, zalcitabine and stavudine develop more slowly and are lower than those seen with zidovudine. Resistance to lamivudine develops rapidly, in weeks to months; selection of a pre-existing mutated viral strain results in a 1000-fold reduction in susceptibility. There is some cross-resistance between nucleoside antiretroviral agents, particularly among didanosine, zalcitabine and lamivudine. SUPPRESSION OF RESISTANCE: Some agents induce mutations that reverse or suppress zidovudine resistance; combination therapy with these drugs may delay the emergence of multidrug-resistance, but the mutational flexibility of the HIV-1 virus means that drug resistant isolates will eventually develop. Combining HIV protease inhibitors that strongly suppress viral replication with nucleoside inhibitors also delays the emergence of resistance. CONCLUSIONS: Widespread use of nucleoside HIV reverse transcriptase inhibitors that incompletely suppress viral replication has led to the emergence of resistant viral strains, with a consequent risk of transmission of drug-resistant virus. Combinations of protease inhibitors and reverse transcriptase inhibitors may slow viral replication sufficiently to prevent generation of resistant virus, to extend the duration of antiviral activity and increase the benefit to patients.

Anti-HIV Agents↗
PubMed1994

Effect of a thiobenzimidazolone derivative on DNA strand transfer catalyzed by HIV-1 reverse transcriptase.

Thiobenzimidazolone (TIBO) derivatives are known inhibitors of the DNA polymerase activity of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT). The effect of a TIBO derivative ((+)-S-4,5,6,7-tetrahydro-9-chloro-5- methyl-6-(3-methyl-2-butenyl)-imidazol[4,5,1-jk]1,4-benzodiazapine -2-thione ) on the DNA strand transfer reaction catalyzed by HIV-1 RT (which is a function of both the DNA polymerase and RNase H activities) was investigated by delineating the effect of the drug on the constitutive DNA polymerase and RNase H activities) was investigated by delineating the effect of the drug on the constitutive DNA polymerase and RNase H activities. Single nucleotide incorporation on template-primer 1 was used to study the DNA polymerase activity of HIV-1 RT while template-primer 2 was used to study the effect of TIBO on the RNase H activity (polymerase independent). The drug was found to decrease the amplitude of the presteady-state burst when preequilibrated with the enzyme-substrate complex besides decreasing the steady-state rate of single nucleotide incorporations. In the absence of preincubation, TIBO did not affect the burst amplitude but decreased the steady-state rate after the pre-transient phase. This suggested that binding of TIBO to RT was affected by the presence of template-primer and required dissociation of the enzyme from the template-primer for effective binding. The polymerase-independent RNase H activity was activated in the presence of TIBO. The effect of TIBO on the overall process of DNA strand transfer is a balance between its inhibition of the polymerase activity and its activation of the RNase H activity.

Antiviral Agents↗
PubMed2025

Kinetic Investigation of Resistance to Islatravir Conferred by Mutations in HIV-1 Reverse Transcriptase.

Islatravir (EFdA) is a novel nucleoside reverse transcriptase translocation inhibitor (NRTTI) that potently blocks HIV-1 replication in vivo. Its unique structural features in contrast to nucleoside reverse transcriptase inhibitors (NRTIs), particularly the 4'-ethynyl and 3'-hydroxy groups, contribute to its high clinical potency. Once intracellularly activated to EFdA 5'-triphosphate (EFdA-TP), it competes with dATP for incorporation by HIV-1 reverse transcriptase (RT) during HIV-1 genomic replication. The 4'-ethynyl group of incorporated EFdA-MP interacts with a hydrophobic pocket of HIV-1 RT, hindering DNA translocation and terminating DNA synthesis. The M184V mutation, commonly associated with resistance to NRTIs such as lamivudine and emtricitabine, and the M184V/A114S mutations, both located within the hydrophobic pocket, were shown to reduce Islatravir susceptibility in cell-based viral resistance selection assays. To elucidate the mechanisms by which these mutations affect Islatravir inhibition, we employed pre-steady-state kinetics to investigate their impact on EFdA-TP incorporation by HIV-1 RT using both DNA and RNA templates. We found that M184V had a modest effect on EFdA-TP incorporation efficiency, increasing it 2-fold with the DNA template and decreasing it 3-fold with the RNA template. In contrast, M184V/A114S significantly inhibited EFdA-TP incorporation, reducing its incorporation efficiency 5.4-fold with the DNA template and 181-fold with the RNA template. These reductions were primarily attributable to corresponding decreases in EFdA-TP incorporation rate constants of 18-fold and 105-fold, respectively. These results suggest that, unlike FDA-approved NRTIs, the clinical efficacy of Islatravir, may not be substantially compromised by the M184V mutation alone but will be significantly reduced by the M184V/A114S mutations.

HIV Reverse Transcriptase↗
PubMed1989

Analysis of the ribonuclease H activity of HIV-1 reverse transcriptase using RNA.DNA hybrid substrates derived from the gag region of HIV-1.

The RNase H activity associated with recombinant p66/p51 HIV-1 reverse transcriptase (RT) has been analyzed in the absence of DNA synthesis by using homogeneous RNA.DNA substrates. The substrates consisted of SP6 runoff transcripts from a portion of the gag region of the HIV-1 genome hybridized to complementary single-stranded DNA from either an M13 subclone or a phagemid transcription vector subclone. The corresponding hybrids either carried a 5'-mismatch of seven nucleotides or were fully base-paired. Analysis of recombinant HIV-1 p66/p51 RT by an activated gel assay employing these substrates suggested that the RNase H activity was exclusively associated with the p66 polypeptide. Denaturing gel electrophoresis was used to analyze the oligonucleotide products generated by hydrolysis of the hybrids by HIV-1 RT, M-MuLV RT, and Escherichia coli RNase H. The significant difference in the time-dependent distribution of products of HIV-1 RT vs E. coli RNase H catalyzed cleavage of 5'-mismatched hybrids indicated that the preparation of recombinant HIV-1 RT was free of contaminating bacterial RNase H. Although the HIV-1 RT associated RNase H activity shares many of the general mechanistic features of other retroviral enzymes [Gerard, G. F. (1981) Biochemistry 20, 256-265], the appearance of unique intermediates and end products in the course of hydrolysis of 5'-mismatched and fully base-paired hybrids indicated a significant difference in the sequence dependence of the kinetics of RNase H cleavage by HIV-1 RT and M-MuLV RT.

Base Sequence↗
PubMed2005

Hypophosphoric acid is a unique substrate of pyrophosphorolysis catalyzed by HIV-1 reverse transcriptase.

Pyrophosphate analogues, namely, pyrophosphorous, hypophosphoric, and hypophosphorous acids, were evaluated as inhibitors in elongation reactions and substrates in pyrophosphorolysis reaction catalyzed by HIV-1 reverse transcriptase and DNA polymerase I (the Klenow fragment). The substrate efficacy of hypophosphoric acid in pyrophosphorolysis reaction exceeded that of pyrophosphate for both enzymes by more than ten times. The product of the reaction was a dNTP analogue bearing a hypophosphate in the beta,gamma-position. Pyrophosphorous and hypophosphorous acids were neither inhibitors nor substrates for the enzymes. Kinetic parameters of the pyrophosphorolysis reaction catalyzed by HIV reverse transcriptase in the presence of hypophosphoric acid were evaluated. The dTMP analogue bearing a hypophosphate in the beta,gamma-position was synthesized and its substrate properties in elongation reaction catalyzed by HIV-1 reverse transcriptase were similar to those of natural dTTP. Hypophosphoric acid was capable of removing ddTMP, ddTMP(3'N3), and ddTMP(3'NH2) from the 3'-end of primers with an equal efficacy.

Base Sequence↗
PubMed1995

Site-directed mutagenesis of arginine 72 of HIV-1 reverse transcriptase. Catalytic role and inhibitor sensitivity.

In order to determine the catalytic role of Arg72 of HIV-1 reverse transcriptase (RT), we carried out site-directed mutagenesis at codon 72. Two mutant proteins (R72A and R72K) were purified and characterized. With Arg to Ala substitution the kcat of the polymerase reaction was reduced by nearly 100-fold with poly(rA) template, but only about 5-15-fold with poly(rC) and poly(dC) templates. The Arg to Lys substitution exhibited a qualitatively similar pattern, although the overall reduction in kcat was less severe. Most interestingly, we noted a large difference in the rate constant of the first and second nucleotide incorporation by R72A, suggesting that Arg72 participates in the reaction after the formation of the first phosphodiester bond. We propose this step to be the pyrophosphate binding and removal step following the nucleotidyltransferase reaction. Support for this proposal is obtained from the observation that the R72A mutant (i) exhibited a pronounced translocation defect in the processivity analysis, (ii) lacked the ability to catalyze pyrophosphorolysis, and (iii) showed complete resistance to phosphonoformate, an analog of PPi.Arg72 is the first residue of HIV-1 RT proposed to be involved in the pyrophosphate binding/removal function of RT.

Arginine↗
PubMed1990

Endoribonucleolytic cleavage of RNA: oligodeoxynucleotide hybrids by the ribonuclease H activity of HIV-1 reverse transcriptase.

Endoribonucleolytic cleavage by the ribonuclease H activity associated with HIV-1 reverse transcriptase was observed in vitro using substrates consisting of synthetic oligodeoxynucleotides hybridized to a 345 nucleotide T7 RNA polymerase transcript derived from the gag region of HIV-1. This observation suggests that a possible mechanism of action of antisense oligonucleotides in the inhibition of viral replication and expression may involve the selective "suicidal" ribonucleolytic cleavage of viral RNA by reverse transcriptase at the site of hybridization of the oligonucleotide.

Base Sequence↗
PubMed1994

Locations of anti-AIDS drug binding sites and resistance mutations in the three-dimensional structure of HIV-1 reverse transcriptase. Implications for mechanisms of drug inhibition and resistance.

The locations of HIV-1 RT nucleoside and non-nucleoside inhibitor-binding sites and inhibitor-resistance mutations are analyzed in the context of the three-dimensional structure of the enzyme and implications for mechanisms of drug inhibition and resistance are discussed. In order to help identify residues that may play a role in inhibitor binding, solvent accessibilities of amino acids that comprise the inhibitor-binding sites in the structure of HIV-1 RT complexed with a dsDNA template-primer are analyzed. While some mutations that cause resistance to nucleoside analogs, such as AZT, ddI, and ddC, are located near enough to the dNTP-binding site to directly interfere with binding of nucleoside analogs, many are located away from the dNTP-binding site and more likely confer resistance by other mechanisms. Many of the latter mutations are located on the surface of the DNA-binding cleft and may lead to altered template-primer positioning or conformation, causing a distortion of the geometry of the polymerase active site and consequent discrimination between normal and altered dNTP substrates. Other nucleoside analog-resistance mutations located on the periphery of the dNTP-binding site may exert their effects via altered interactions with dNTP-binding site residues. The structure of the hydrophobic region in HIV-1 RT that binds non-nucleoside inhibitors, for example, nevirapine and TIBO, has been analyzed in the absence of bound ligand. The pocket that is present when non-nucleoside inhibitors are bound is not observed in the inhibitor-free structure of HIV-1 RT with dsDNA. In particular it is filled by Tyr181 and Tyr188, suggesting that the pocket is formed primarily by rotation of these large aromatic side-chains. Existing biochemical data, taken together with the three-dimensional structure of HIV-1 RT, makes it possible to propose potential mechanisms of inhibition by non-nucleoside inhibitors. One such mechanism is local distortion of HIV-1 RT structural elements thought to participate in catalysis: the beta 9-beta 10 hairpin (which contains polymerase active site residues) and the beta 12-beta 13 hairpin ("primer grip"). An alternative possibility is restricted mobility of the p66 thumb subdomain, which is supported by the observation that structural elements of the non-nucleoside inhibitor-binding pocket may act as a "hinge" for the thumb.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMedDate not supplied

The rationale for a study on HIV-1 reverse transcriptase mutations and outcome of antiretroviral therapy with two nucleoside analogs.

The development of resistance to antiretroviral drugs has been recognized as an important cause of treatment failure in HIV-1-infected patients; however the correlation between emergence of resistance and treatment failure has not been yet clearly defined. The high rate of viral replication, together with the lack of proof reading activity of HIV-1 reverse transcriptase, accounts for the rapid establishment of extensive genotypic variation, resulting in the emergence of viral mutants showing primary or secondary resistance to antiretroviral drugs. In this regard, phenotyping and genotyping allow the detection of drug resistance. Both tests have advantages and limitations compared to each other. The complete suppression of viral replication seems to be the best way to avoid occurrence of drug resistance, and viral loads below the limit of detection can be usually achieved by a combination of 3 antiretroviral drugs. In this scenario, the proportion of HIV-1-infected patients on dual therapy is still relevant in Italy. We believe that the study of this subset of individuals is very important, as resistance to nucleoside analogues may impair the outcome of a future triple therapy. In addition, this study could contribute to define the role of resistance assays in the management of HIV-1-infected patients.

Anti-HIV Agents↗
PubMed1999

Sensitivity and resistance to (+)-calanolide A of wild-type and mutated forms of HIV-1 reverse transcriptase.

We have tested both wild-type and drug-resistant mutated, recombinant human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) molecules for sensitivity to each of two non-nucleoside RT inhibitors (NNRTI), (+)-calanolide A and nevirapine, in primer extension assays. We found that RT containing either the V106A or Y181C substitutions, associated with NNRTI resistance, displayed approximately 90-fold resistance to nevirapine but remained fully sensitive to (+)-calanolide A and that the Y181C mutation marginally enhanced susceptibility to the latter drug. In contrast, the Y188H substitution in RT resulted in about 30-fold resistance to (+)-calanolide A in these assays but did not result in diminished sensitivity to nevirapine. Tissue culture results indicated that the combination of (+)-calanolide A and nevirapine possessed an additive to weakly synergistic effect in blocking replication of HIV-1 in tissue culture. These results suggest that (+)-calanolide A and nevirapine might have rationale as a combination therapy for HIV disease.

Coumarins↗
PubMed2003

APHS can act synergically with clinically available HIV-1 reverse transcriptase and protease inhibitors and is active against several drug-resistant HIV-1 strains in vitro.

OBJECTIVES: The use of multiple drug combinations in current anti-human immunodeficiency virus (HIV) therapy allows lower dosages of individual drugs and results in enhancement of the therapeutic effect due to synergic interactions between different drugs. We have shown that o-(acetoxyphenyl)hept-2-ynyl sulphide (APHS), a recently developed non-steroidal anti-inflammatory drug, shows anti-HIV activity in a dose-dependent manner. The first aim of this study was to investigate whether APHS can act synergically with the clinically available reverse transcriptase and protease inhibitors (RTIs and PIs, respectively) in vitro. Because of the increasing prevalence of RTI- and PI-resistant HIV-1 strains, the second aim of this study was to assess the antiviral activity of APHS against drug-resistant HIV-1 strains in vitro. MATERIALS AND METHODS: HIV-infected peripheral blood mononuclear cells (PBMC) were treated for 7 days with different combinations of APHS and RTIs or PIs. The MT-2 cell line was infected with different HIV-1 strains and treated with APHS for 5 days. RESULTS: APHS showed synergic interactions with the RTIs zidovudine, lamivudine and efavirenz and with the PIs indinavir and ritonavir. The 50% inhibitory concentration (IC50) of APHS in this assay dropped from 13 microM when used alone, to 5 micro M after combination with an RTI or PI. In combination with APHS the IC50 of the RTI and PI drugs tested also dropped. APHS inhibits the replication of HIV-1 strains resistant to zidovudine, lamivudine, stavudine, didanosine, zalcitabine and ritonavir. CONCLUSIONS: These results indicate that APHS can be combined with RTIs and PIs and can inhibit several NRTI and PI-resistant HIV-1 strains.

Alkynes↗
PubMed2006

QSAR for non-nucleoside inhibitors of HIV-1 reverse transcriptase.

By means of QSAR algorithms we model the potency pIC(90) [mM] of 154 non-nucleoside reverse transcriptase inhibitors (NNRTI) of the wild-type HIV-1 virus, considered as the second generation analogues of Efavirenz. In addition, 56 inhibitors of the K-103N viral mutant form are also investigated. A pool of 1494 theoretical molecular descriptors provided mainly by the Dragon 5 software is explored by several methods of variable selection: forward stepwise regression, the replacement method, and the genetic algorithm approach. The optimal models found include up to seven parameters: R = 0.7991, R(l-20%-o) = 0.7233 for the case of wild-type, and R = 0.9261, R(l-5%-o) = 0.8802 for the K-103N mutation.

Alkynes↗