Cryptococcosis is an invasive infection that accounts for 15% of AIDS-related fatalities. Still, treating cryptococcosis remains a significant challenge due to the poor availability of effective antifungal therapies and emergence of drug resistance. Interestingly, protease inhibitor components of antiretroviral therapy regimens have shown some clinical benefits in these opportunistic infections. We investigated Major aspartyl peptidase 1 (May1), a secreted Cryptococcus neoformans protease, as a possible target for the development of drugs that act against both fungal and retroviral aspartyl proteases. Here, we describe the biochemical characterization of May1, present its high-resolution X-ray structure, and provide its substrate specificity analysis. Through combinatorial screening of 11,520 compounds, we identified a potent inhibitor of May1 and HIV protease. This dual-specificity inhibitor exhibits antifungal activity in yeast culture, low cytotoxicity, and low off-target activity against host proteases and could thus serve as a lead compound for further development of May1 and HIV protease inhibitors.

• MeSH
• antifungální látky chemie   metabolismus   farmakologie   MeSH
• aspartátové proteasy antagonisté a inhibitory   genetika   metabolismus   MeSH
• Cryptococcus neoformans enzymologie   MeSH
• fungální proteiny antagonisté a inhibitory   genetika   metabolismus   MeSH
• HIV-proteasa chemie   metabolismus   MeSH
• HIV enzymologie   MeSH
• houby účinky léků   MeSH
• katalytická doména MeSH
• krystalografie rentgenová MeSH
• preklinické hodnocení léčiv MeSH
• rekombinantní proteiny biosyntéza   chemie   izolace a purifikace   MeSH
• simulace molekulární dynamiky MeSH
• substrátová specifita MeSH
• vazebná místa MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• antifungální látky MeSH
• aspartátové proteasy MeSH
• fungální proteiny MeSH
• HIV-proteasa MeSH
• rekombinantní proteiny MeSH

Transient and fuzzy intermolecular interactions are fundamental to many biological processes. Despite their importance, they are notoriously challenging to characterize. Effects induced by paramagnetic ligands in the NMR spectra of interacting biomolecules provide an opportunity to amplify subtle manifestations of weak intermolecular interactions observed for diamagnetic ligands. Here, we present an approach to characterizing dynamic interactions between a partially flexible dimeric protein, HIV-1 protease, and a metallacarborane-based ligand, a system for which data obtained by standard NMR approaches do not enable detailed structural interpretation. We show that for the case where the experimental data are significantly averaged to values close to zero the standard fitting of pseudocontact shifts cannot provide reliable structural information. We based our approach on generating a large ensemble of full atomic models, for which the experimental data can be predicted, ensemble averaged and finally compared to the experiment. We demonstrate that a combination of paramagnetic NMR experiments, quantum chemical calculations, and molecular dynamics simulations offers a route towards structural characterization of dynamic protein-ligand complexes.

• MeSH
• borany chemie   MeSH
• HIV-proteasa chemie   MeSH
• konformace proteinů MeSH
• kovy chemie   MeSH
• kvantová teorie MeSH
• ligandy MeSH
• magnetická rezonanční spektroskopie metody   MeSH
• simulace molekulární dynamiky * MeSH
• vazba proteinů MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• borany MeSH
• HIV-proteasa MeSH
• kovy MeSH
• ligandy MeSH
• p16 protease, Human immunodeficiency virus 1 MeSH Prohlížeč

High-pressure methods have become an interesting tool of investigation of structural stability of proteins. They are used to study protein unfolding, but dissociation of oligomeric proteins can be addressed this way, too. HIV-1 protease, although an interesting object of biophysical experiments, has not been studied at high pressure yet. In this study HIV-1 protease is investigated by high pressure (up to 600 MPa) fluorescence spectroscopy of either the inherent tryptophan residues or external 8-anilino-1-naphtalenesulfonic acid at 25°C. A fast concentration-dependent structural transition is detected that corresponds to the dimer-monomer equilibrium. This transition is followed by a slow concentration independent transition that can be assigned to the monomer unfolding. In the presence of a tight-binding inhibitor none of these transitions are observed, which confirms the stabilizing effect of inhibitor. High-pressure enzyme kinetics (up to 350 MPa) also reveals the stabilizing effect of substrate. Unfolding of the protease can thus proceed only from the monomeric state after dimer dissociation and is unfavourable at atmospheric pressure. Dimer-destabilizing effect of high pressure is caused by negative volume change of dimer dissociation of -32.5 mL/mol. It helps us to determine the atmospheric pressure dimerization constant of 0.92 μM. High-pressure methods thus enable the investigation of structural phenomena that are difficult or impossible to measure at atmospheric pressure.

• MeSH
• anilin-naftalen sulfonáty metabolismus   MeSH
• atmosférický tlak MeSH
• darunavir metabolismus   MeSH
• dimerizace MeSH
• fluorescenční spektrometrie MeSH
• HIV-proteasa chemie   metabolismus   MeSH
• inhibitory HIV-proteasy metabolismus   MeSH
• kinetika MeSH
• konformace proteinů MeSH
• lidé MeSH
• molekulární modely MeSH
• multimerizace proteinu MeSH
• sbalování proteinů * MeSH
• stabilita proteinů účinky léků   MeSH
• termodynamika MeSH
• tryptofan metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1-anilino-8-naphthalenesulfonate MeSH Prohlížeč
• anilin-naftalen sulfonáty MeSH
• darunavir MeSH
• HIV-proteasa MeSH
• inhibitory HIV-proteasy MeSH
• p16 protease, Human immunodeficiency virus 1 MeSH Prohlížeč
• tryptofan MeSH

HIV protease (PR) is required for proteolytic maturation in the late phase of HIV replication and represents a prime therapeutic target. The regulation and kinetics of viral polyprotein processing and maturation are currently not understood in detail. Here we design, synthesize, validate and apply a potent, photodegradable HIV PR inhibitor to achieve synchronized induction of proteolysis. The compound exhibits subnanomolar inhibition in vitro. Its photolabile moiety is released on light irradiation, reducing the inhibitory potential by 4 orders of magnitude. We determine the structure of the PR-inhibitor complex, analyze its photolytic products, and show that the enzymatic activity of inhibited PR can be fully restored on inhibitor photolysis. We also demonstrate that proteolysis of immature HIV particles produced in the presence of the inhibitor can be rapidly triggered by light enabling thus to analyze the timing, regulation and spatial requirements of viral processing in real time.

• MeSH
• aminokumariny chemická syntéza   farmakologie   MeSH
• časové faktory MeSH
• fotolýza MeSH
• HEK293 buňky MeSH
• HIV-1 účinky léků   fyziologie   účinky záření   MeSH
• HIV-proteasa chemie   metabolismus   MeSH
• inhibitory HIV-proteasy chemická syntéza   farmakologie   MeSH
• karbamáty chemická syntéza   farmakologie   MeSH
• kinetika MeSH
• lidé MeSH
• molekulární modely MeSH
• proteinové prekurzory antagonisté a inhibitory   chemie   metabolismus   MeSH
• proteolýza účinky léků   MeSH
• replikace viru MeSH
• světlo MeSH
• valin analogy a deriváty   chemická syntéza   farmakologie   MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aminokumariny MeSH
• HIV-proteasa MeSH
• inhibitory HIV-proteasy MeSH
• karbamáty MeSH
• p55 gag precursor protein, Human immunodeficiency virus 1 MeSH Prohlížeč
• proteinové prekurzory MeSH
• thiazol-5-ylmethyl (5-(2-amino-3-methylbutanamido)-3-hydroxy-1,6-diphenylhexan-2-yl)carbamate MeSH Prohlížeč
• valin MeSH

High-pressure methods have become attractive tools for investigation of the structural stability of proteins. Besides protein unfolding, dimerization can be studied this way, too. HIV-1 protease is a convenient target of experimental and theoretical high-pressure studies. In this study molecular-dynamics simulations are used to predict the response of HIV-1 protease to the pressure of 0.1 to 600 MPa. The protease conformation of both the monomer and the dimer is highly rigid changing insignificantly with growing pressure. Hydrophobicity of the protease decreases with increasing pressure. Water density inside the active-site cavity grows from 87% to 100% of the bulk water density within the pressure range. The dimer-dissociation volume change is negative for most of the pressure ranges with the minimum of -105 ml mol(-1), except for a short interval of positive values at low pressures. The dimer is thus slightly stabilized up to 160 MPa, but strongly destabilized by higher pressures.

• MeSH
• dimerizace MeSH
• HIV-proteasa chemie   metabolismus   MeSH
• konformace proteinů MeSH
• simulace molekulární dynamiky * MeSH
• stabilita proteinů MeSH
• Publikační typ
• časopisecké články MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• HIV-proteasa MeSH
• p16 protease, Human immunodeficiency virus 1 MeSH Prohlížeč

HIV protease (PR) is a key target for antiviral drugs, and HIV protease inhibitors (PIs) are a prime example of successful structure-based drug design. PIs show clear therapeutic benefits, but their efficacy can be compromised by poor bioavailabilitity, unwanted side effects, and most importantly, development of antiviral drug resistance. Therefore, the quest for novel, highly active compounds with improved resistance profiles, better pharmacokinetic properties, and fewer adverse effects continues. In particular, the problem of cross-resistance could be circumvented by identifying novel compounds that show different binding modes to HIV PR than the current clinical inhibitors.

• MeSH
• cílená molekulární terapie metody   MeSH
• HIV-proteasa chemie   metabolismus   MeSH
• inhibitory HIV-proteasy chemická syntéza   chemie   MeSH
• katalytická doména MeSH
• lidé MeSH
• molekulární struktura MeSH
• peptidomimetika chemická syntéza   chemie   MeSH
• racionální návrh léčiv * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• HIV-proteasa MeSH
• inhibitory HIV-proteasy MeSH
• peptidomimetika MeSH

BACKGROUND: Apoptosis is one of the presumptive causes of CD4+ T cell depletion during HIV infection and progression to AIDS. However, the precise role of HIV-1 in this process remains unexplained. HIV-1 protease (PR) has been suggested as a possible factor, but a direct link between HIV-1 PR enzymatic activity and apoptosis has not been established. RESULTS: Here, we show that expression of active HIV-1 PR induces death in HeLa and HEK-293 cells via the mitochondrial apoptotic pathway. This conclusion is based on in vivo observations of the direct localization of HIV-1 PR in mitochondria, a key player in triggering apoptosis. Moreover, we observed an HIV-1 PR concentration-dependent decrease in mitochondrial membrane potential and the role of HIV-1 PR in activation of caspase 9, PARP cleavage and DNA fragmentation. In addition, in vitro data demonstrated that HIV-1 PR mediates cleavage of mitochondrial proteins Tom22, VDAC and ANT, leading to release of AIF and Hsp60 proteins. By using yeast two-hybrid screening, we also identified a new HIV-1 PR interaction partner, breast carcinoma-associated protein 3 (BCA3). We found that BCA3 accelerates p53 transcriptional activity on the bax promoter, thus elevating the cellular level of pro-apoptotic Bax protein. CONCLUSION: In summary, our results describe the involvement of HIV-1 PR in apoptosis, which is caused either by a direct effect of HIV-1 PR on mitochondrial membrane integrity or by its interaction with cellular protein BCA3.

• MeSH
• adaptorové proteiny signální transdukční genetika   metabolismus   MeSH
• apoptóza genetika   MeSH
• buněčné linie MeSH
• CD4-pozitivní T-lymfocyty metabolismus   MeSH
• fragmentace DNA MeSH
• HEK293 buňky MeSH
• HeLa buňky MeSH
• HIV infekce genetika   metabolismus   MeSH
• HIV-1 genetika   metabolismus   MeSH
• HIV-proteasa genetika   metabolismus   MeSH
• jaderné proteiny genetika   metabolismus   MeSH
• lidé MeSH
• mitochondriální proteiny genetika   metabolismus   MeSH
• mitochondrie genetika   metabolismus   MeSH
• nádorové buněčné linie MeSH
• nádorový supresorový protein p53 genetika   metabolismus   MeSH
• promotorové oblasti (genetika) genetika   MeSH
• protein X asociovaný s bcl-2 genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adaptorové proteiny signální transdukční MeSH
• AKIP1 protein, human MeSH Prohlížeč
• BAX protein, human MeSH Prohlížeč
• HIV-proteasa MeSH
• jaderné proteiny MeSH
• mitochondriální proteiny MeSH
• nádorový supresorový protein p53 MeSH
• p16 protease, Human immunodeficiency virus 1 MeSH Prohlížeč
• protein X asociovaný s bcl-2 MeSH
• TP53 protein, human MeSH Prohlížeč

UNLABELLED: We report enzymologic, thermodynamic and structural analyses of a series of six clinically derived mutant HIV proteases (PR) resistant to darunavir. As many as 20 mutations in the resistant PRs decreased the binding affinity of darunavir by up to 13 000-fold, mostly because of a less favorable enthalpy of binding that was only partially compensated by the entropic contribution. X-ray structure analysis suggested that the drop in enthalpy of darunavir binding to resistant PR species was mostly the result of a decrease in the number of hydrogen bonds and a loosening of the fit between the inhibitor and the mutated enzymes. The favorable entropic contribution to darunavir binding to mutated PR variants correlated with a larger burial of the nonpolar solvent-accessible surface area upon inhibitor binding. We show that even very dramatic changes in the PR sequence leading to the loss of hydrogen bonds with the inhibitor could be partially compensated by the entropy contribution as a result of the burial of the larger nonpolar surface area of the mutated HIV PRs. DATABASE: Atomic coordinates and structure factors for the crystal structures PRwt-DRV and PRDRV2-DRV complex have been deposited in the Protein Data Bank under accession codes 4LL3 and 3TTP, respectively. STRUCTURED DIGITAL ABSTRACT: • PR and PR bind by x-ray crystallography (View interaction).

• Klíčová slova
• HIV protease inhibitors, X‐ray crystallography, enthropic contribution, isothermal titration calorimetry, resistance mutation,
• MeSH
• darunavir MeSH
• HIV-proteasa chemie   genetika   metabolismus   MeSH
• inhibitory HIV-proteasy chemie   farmakologie   MeSH
• molekulární sekvence - údaje MeSH
• mutace * MeSH
• sekvence aminokyselin MeSH
• simulace molekulového dockingu * MeSH
• sulfonamidy chemie   farmakologie   MeSH
• termodynamika MeSH
• vazba proteinů MeSH
• virová léková rezistence genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• darunavir MeSH
• HIV-proteasa MeSH
• inhibitory HIV-proteasy MeSH
• p16 protease, Human immunodeficiency virus 1 MeSH Prohlížeč
• sulfonamidy MeSH

Insertions in the protease (PR) region of human immunodeficiency virus (HIV) represent an interesting mechanism of antiviral resistance against HIV PR inhibitors (PIs). Here, we demonstrate the improved ability of a phosphonate-containing experimental HIV PI, GS-8374, relative to that of other PIs, to effectively inhibit patient-derived recombinant HIV strains bearing PR insertions and numerous other mutations. We correlate enzyme inhibition with the catalytic activities of corresponding recombinant PRs in vitro and provide a biochemical and structural analysis of the PR-inhibitor complex.

• MeSH
• HIV infekce farmakoterapie   virologie   MeSH
• HIV-1 chemie   účinky léků   enzymologie   genetika   MeSH
• HIV-proteasa chemie   genetika   metabolismus   MeSH
• inhibitory HIV-proteasy chemie   farmakologie   MeSH
• inzerční mutageneze * MeSH
• krystalografie rentgenová MeSH
• lidé MeSH
• molekulární modely MeSH
• organofosfonáty analýza   MeSH
• sekvence aminokyselin MeSH
• vazebná místa MeSH
• virová léková rezistence MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• HIV-proteasa MeSH
• inhibitory HIV-proteasy MeSH
• organofosfonáty MeSH
• p16 protease, Human immunodeficiency virus 1 MeSH Prohlížeč

Human immunodeficiency virus 1 protease (HIV-1 PR), an important therapeutic target for the treatment of AIDS, is one of the most well-studied enzymes. However, there is still much to learn about the regulation of the activity and inhibition of this key viral enzyme. Specifically, the mechanism of activation of HIV-1 PR from the viral polyprotein upon HIV maturation is still not understood. It has been suggested that external factors like pH or salt concentration might contribute to regulation of this crucial step in the viral life cycle. Recently, we analyzed the activity of HIV-1 PR in aqueous solutions of sodium and potassium chloride by experimental determination of enzyme kinetics and molecular dynamics simulations. We showed that the effect of salt concentration is cation-specific [Heyda et al., Phys. Chem. Chem. Phys., 2009 (11), 7599]. In this study, we extended this analysis for other alkali cations and found that the dependence of the initial velocity of peptide substrate hydrolysis on the nature of the cation follows the Hofmeister series, with the exception of caesium. Significantly higher catalytic efficiencies both in terms of substrate binding (K(M)) and turnover number (kcat) are observed in the presence of K+ compared to Na+ or Li+ at corresponding salt concentrations. Molecular dynamics simulations suggest that both lithium and sodium are attracted more strongly than potassium and caesium to the protein surface, mostly due to stronger interactions with carboxylate side chain groups of aspartates and glutamates. Furthermore, we observed a surprising decrease in the K(M) value for a specific substrate at very low salt concentration. The molecular mechanism of this phenomenon will be further analyzed.

• MeSH
• alkálie chemie   MeSH
• biokatalýza MeSH
• HIV-proteasa metabolismus   MeSH
• kationty chemie   MeSH
• koncentrace vodíkových iontů MeSH
• simulace molekulární dynamiky MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• alkálie MeSH
• HIV-proteasa MeSH
• kationty MeSH
• p16 protease, Human immunodeficiency virus 1 MeSH Prohlížeč