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Fulltext Identifications of drug resistance mutations among antiretroviral treatment naive HIV-1 patients in Peninsular Malaysia

Zain RM, Ibrahim N, Ismail S, Suppiah J, Mat Rahim NA, Thayan R

Asian Pac J Trop Med, 2017 Jan;10(1):75-78.
PMID: 28107870 DOI: 10.1016/j.apjtm.2016.12.005

OBJECTIVE: To determine drug resistance mutations and the HIV-1 subtypes among antiretroviral treatment naive HIV-1 patients in Peninsular Malaysia.
METHODS: A total of 45 samples from four hospitals that provide HIV viral load services were subjected to the amplification of the protease and two third of reverse transcriptase regions of the pol gene by RT-PCR and Sanger sequencing. Drug resistance mutation (DRM) interpretation reports the presence of mutations related to protease inhibitors (PIs), Nucleoside reverse-transcriptase inhibitors (NRTI) and Non-nucleoside reverse-transcriptase inhibitors (NNRTI) based on analysis using Stanford HIV database program.
RESULTS: DRMs were identified in 35% of patients, among which 46.7% of them showed minor resistance to protease inhibitor with A71V and L10l were the commonest DRMs detected. About 21.4% and 50.0% of patients had mutations to NRTIs and NNRTIs, respectively. CRF01_AE was found to be the predominant HIV-1 subtype.
CONCLUSIONS: These findings have served as an initial crucial data in determining the prevalence of transmitted HIV-1 drug resistance for the country. However, more samples from various parts of the country need to be accumulated and analyzed to provide overall HIV-1 drug resistance in the country.

Matched MeSH terms: Protease Inhibitors
Binding specificity of polypeptide substrates in NS2B/NS3pro serine protease of dengue virus type 2: A molecular dynamics Study

Yotmanee P, Rungrotmongkol T, Wichapong K, Choi SB, Wahab HA, Kungwan N, et al.

J Mol Graph Model, 2015 Jul;60:24-33.
PMID: 26086900 DOI: 10.1016/j.jmgm.2015.05.008

The pathogenic dengue virus (DV) is a growing global threat, particularly in South East Asia, for which there is no specific treatment available. The virus possesses a two-component (NS2B/NS3) serine protease that cleaves the viral precursor proteins. Here, we performed molecular dynamics simulations of the NS2B/NS3 protease complexes with six peptide substrates (capsid, intNS3, 2A/2B, 4B/5, 3/4A and 2B/3 containing the proteolytic site between P(1) and P(1)' subsites) of DV type 2 to compare the specificity of the protein-substrate binding recognition. Although all substrates were in the active conformation for cleavage reaction by NS2B/NS3 protease, their binding strength was somewhat different. The simulated results of intermolecular hydrogen bonds and decomposition energies suggested that among the ten substrate residues (P(5)-P(5)') the P(1) and P(2) subsites play a major role in the binding with the focused protease. The arginine residue at these two subsites was found to be specific preferential binding at the active site with a stabilization energy of intNS3>2A/2B>4B/5>3/4A>2B/3 in a relative correspondence with previous experimentally derived values.

Matched MeSH terms: Protease Inhibitors/chemistry
The aminopeptidase inhibitor, z-L-CMK, is toxic and induces cell death in Jurkat T cells through oxidative stress

Yeo EH, Goh WL, Chow SC

Toxicol. Mech. Methods, 2018 Mar;28(3):157-166.
PMID: 28849708 DOI: 10.1080/15376516.2017.1373882

The leucine aminopeptidase inhibitor, benzyloxycarbonyl-leucine-chloromethylketone (z-L-CMK), was found to be toxic and readily induce cell death in Jurkat T cells. Dose-response studies show that lower concentration of z-L-CMK induced apoptosis in Jurkat T cells whereas higher concentration causes necrosis. In z-L-CMK-induced apoptosis, both the initiator caspases (-8 and -9) and effector caspases (-3 and -6) were processed to their respective subunits. However, the caspases remained intact in z-L-CMK-induced necrosis. The caspase inhibitor, z-VAD-FMK inhibited z-L-CMK-mediated apoptosis and caspase processing but has no effect on z-L-CMK-induced necrosis in Jurkat T cells. The high mobility group protein B1 (HMGB1) protein was found to be released into the culture medium by the necrotic cells and not the apoptotic cells. These results indicate that the necrotic cell death mediated by z-L-CMK at high concentrations is via classical necrosis rather than secondary necrosis. We also demonstrated that cell death mediated by z-L-CMK was associated with oxidative stress via the depletion of intracellular glutathione (GSH) and increase in reactive oxygen species (ROS), which was blocked by N-acetyl cysteine. Taken together, the results demonstrated that z-L-CMK is toxic to Jurkat T cells and induces apoptosis at low concentrations, while at higher concentrations the cells die of necrosis. The toxic side effects in Jurkat T cells mediated by z-L-CMK are associated with oxidative stress via the depletion of GSH and accumulation of ROS.

Matched MeSH terms: Protease Inhibitors/toxicity*; Protease Inhibitors/chemistry
The long-term outcomes of antiretroviral treatment initiated with mono or dual nucleoside reverse transcriptase inhibitors in HIV-1-infected children: an Asian observational study

Wittawatmongkol O, Mohamed TJ, Le TP, Ung V, Maleesatharn A, Hansudewechakul R, et al.

Journal of virus eradication, 2015 06 30;1(3):192-195.
PMID: 27076917

After a median of 115.9 months of follow-up, 90% of 206 HIV-1-infected children in a cohort in Asia who initiated antiretroviral treatment (ART) with mono or dual nucleoside reverse transcriptase inhibitors were alive and had comparable immunological and virological outcomes as compared to the 1,915 children who had started with highly active antiretroviral regimens. However, these children had higher rates of treatment-related adverse events, opportunistic infections, and cumulative mortality, and were more likely to require protease inhibitor-containing regimens or other more novel ART-based regimens.

Matched MeSH terms: Protease Inhibitors
Fulltext Directly Acting Antivirals for COVID-19: Where Do We Stand?

Teoh SL, Lim YH, Lai NM, Lee SWH

Front Microbiol, 2020;11:1857.
PMID: 32849448 DOI: 10.3389/fmicb.2020.01857

The outbreak of a novel coronavirus (SARS-CoV-2) in Wuhan, China in December 2019 has now become a pandemic with no approved therapeutic agent. At the moment, the genomic structure, characteristics, and pathogenic mechanisms of SARS-CoV-2 have been reported. Based upon this information, several drugs including the directly acting antivirals have been proposed to treat people with coronavirus disease 2019 (COVID-19). This rapid review aims to describe the directly acting antivirals that have been examined for use in the management of COVID-19. Searches were conducted in three electronic databases, supplemented with a search on arXiv, bioRxiv, medRxiv, ChinaXiv, ClinicalTrials.gov, and Chinese Clinical Trial Registry for studies examining the use of antivirals in COVID-19 to identify for case reports, case series, observational studies, and randomized controlled studies describing the use of antivirals in COVID-19. Data were extracted independently and presented narratively. A total of 98 studies were included, comprising of 38 published studies and 60 registered clinical trials. These drugs include the broad spectrum antivirals such as umifenovir, protease inhibitors such as lopinavir/ritonavir as well as the RNA-dependent RNA polymerase inhibitors, remdesivir, and favipiravir. Other drugs that have been used include the nucleosidase inhibitors and polymerase acidic endonuclease inhibitors which are currently approved for prevention of influenza infections. While some of the drugs appear promising in small case series and reports, more clinical trials currently in progress are required to provide higher quality evidence.

Matched MeSH terms: Protease Inhibitors
Investigation of interpolymer complexation between Carbopol and various grades of polyvinylpyrrolidone and effects on adhesion strength and swelling properties

Tan YT, Peh KK, Al-Hanba O

J Pharm Pharm Sci, 2001 Jan-Apr;4(1):7-14.
PMID: 11302785

To investigate the interpolymer complexation between Carbopol 934P (CP) and various grades of polyvinylpyrrolidone (PVP) (K90, K32, C15, and VA/S-630).

Matched MeSH terms: Protease Inhibitors/chemistry
Genetic studies of water buffalo blood markers. I. Red cell acid phosphatase, albumin, catalase, red cell alpha-esterase-3, group-specific component, and protease inhibitor

Tan SG, Barker JS, Selvaraj OS, Mukherjee TK, Wong YF

Biochem Genet, 1993 Jun;31(5-6):223-30.
PMID: 8259925

We have developed the methodologies for typing and family studies to establish the modes of inheritance of water buffalo red cell acid phosphatase (Acp), protease inhibitor (Pi), and group-specific component (Gc) on isoelectric focusing and albumin (Alb), red cell alpha-esterase-3 (Est-3), and catalase (Cat) on polyacrylamide gel electrophoresis. Family studies showed that Pi, Gc, Alb, and Cat are coded by autosomal genes with two codominant alleles, while Est-3 is autosomal with two codominant alleles and a recessive null allele and Acp exhibits three codominant alleles.

Matched MeSH terms: Protease Inhibitors/blood
Natural DENV-2 NS2B/NS3 protease inhibitors from Myristica cinnamomea King

Sivasothy Y, Liew SY, Othman MA, Abdul Wahab SM, Hariono M, Mohd Nawi MS, et al.

Trop Biomed, 2021 Jun 01;38(2):79-84.
PMID: 33973577 DOI: 10.47665/tb.38.2.044

The NS2B/NS3 protease is crucial for the pathogenesis of the DENV. Therefore, the inhibition of this protease is considered to be the key strategy for the development of new antiviral drugs. In the present study, malabaricones C (3) and E (4), acylphenols from the fruits of Myristica cinnamomea King, have been respectively identified as moderate (27.33 ± 5.45 μM) and potent (7.55 ± 1.64 μM) DENV-2 NS2B/NS3 protease inhibitors, thus making this the first report on the DENV-2 NS2B/NS3 protease inhibitory activity of acylphenols. Based on the molecular docking studies, compounds 3 and 4 both have π-π interactions with Tyr161. While compound 3 has hydrogen bonding interactions with Gly151, Gly153 and Tyr161, compound 4 however, forms hydrogen bonds with Ser135, Asp129, Phe130 and Ile86 instead. The results from the present study suggests that malabaricones C (3) and E (4) could be employed as lead compounds for the development of new dengue antivirals from natural origin.

Matched MeSH terms: Protease Inhibitors
Fulltext Regulation of Proteolytic Activity to Improve the Recovery of Macrobrachium rosenbergii Nodavirus Capsid Protein

Selvaraj BA, Mariatulqabtiah AR, Ho KL, Ng CL, Yong CY, Tan WS

Int J Mol Sci, 2021 Aug 13;22(16).
PMID: 34445426 DOI: 10.3390/ijms22168725

The causative agent of white tail disease (WTD) in the giant freshwater prawn is Macrobrachium rosenbergii nodavirus (MrNV). The recombinant capsid protein (CP) of MrNV was previously expressed in Escherichia coli, and it self-assembled into icosahedral virus-like particles (VLPs) with a diameter of approximately 30 nm. Extensive studies on the MrNV CP VLPs have attracted widespread attention in their potential applications as biological nano-containers for targeted drug delivery and antigen display scaffolds for vaccine developments. Despite their advantageous features, the recombinant MrNV CP VLPs produced in E. coli are seriously affected by protease degradations, which significantly affect the yield and stability of the VLPs. Therefore, the aim of this study is to enhance the stability of MrNV CP by modulating the protease degradation activity. Edman degradation amino acid sequencing revealed that the proteolytic cleavage occurred at arginine 26 of the MrNV CP. The potential proteases responsible for the degradation were predicted in silico using the Peptidecutter, Expasy. To circumvent proteolysis, specific protease inhibitors (PMSF, AEBSF and E-64) were tested to reduce the degradation rates. Modulation of proteolytic activity demonstrated that a cysteine protease was responsible for the MrNV CP degradation. The addition of E-64, a cysteine protease inhibitor, remarkably improved the yield of MrNV CP by 2.3-fold compared to the control. This innovative approach generates an economical method to improve the scalability of MrNV CP VLPs using individual protease inhibitors, enabling the protein to retain their structural integrity and stability for prominent downstream applications including drug delivery and vaccine development.

Matched MeSH terms: Protease Inhibitors/pharmacology
NS3 protease of Langat tick-borne flavivirus cleaves serine protease substrates

Scaramozzino N, Crance JM, Drouet C, Roebuck JP, Drouet E, Jouan A, et al.

Biochem Biophys Res Commun, 2002 May 31;294(1):16-22.
PMID: 12054734

Langat (LGT) virus, initially isolated in 1956 from ticks in Malaysia, is a naturally occurring nonpathogenic virus with a very close antigenicity to the highly pathogenic tick-borne encephalitis (TBE) Western subtype virus and TBE Far Eastern subtype virus. NS3, the second largest viral protein of LGT virus, is highly conserved among flaviviruses and contains a characteristic protease moiety (NS3 pro). NS3 pro represents an attractive target for anti-protease molecules against TBE virus. We report herein a purification method specially designed for NS3 pro of LGT using a strategy for proper refolding coupled with the enzymatic characterisation of the protein. Different p-nitroanilide substrates, defined on canonic sequences for their susceptibility to Ser-protease, were applied to the proteolytic assays of the protein. The highest values were obtained from substrates containing an Arg or Lys (amino acid) residue at the P1 position. This purification method will facilitate the future development of reliable testing procedures for anti-proteases directed to NS3 proteins.

Matched MeSH terms: Protease Inhibitors/therapeutic use
Fulltext Key drug-targeting genes in pancreatic ductal adenocarcinoma

Sakharkar MK, Dhillon SK, Mazumder M, Yang J

Genes Cancer, 2021;12:12-24.
PMID: 33884102 DOI: 10.18632/genesandcancer.210

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal type of cancer. In this study, we undertook a pairwise comparison of gene expression pattern between tumor tissue and its matching adjacent normal tissue for 45 PDAC patients and identified 22 upregulated and 32 downregulated genes. PPI network revealed that fibronectin 1 and serpin peptidase inhibitor B5 were the most interconnected upregulated-nodes. Virtual screening identified bleomycin exhibited reasonably strong binding to both proteins. Effect of bleomycin on cell viability was examined against two PDAC cell lines, AsPC-1 and MIA PaCa-2. AsPC-1 did not respond to bleomycin, however, MIA PaCa-2 responded to bleomycin with an IC50 of 2.6 μM. This implicates that bleomycin could be repurposed for the treatment of PDAC, especially in combination with other chemotherapy agents. In vivo mouse xenograft studies and patient clinical trials are warranted to understand the functional mechanism of bleomycin towards PDAC and optimize its therapeutic efficacy. Furthermore, we will evaluate the antitumor activity of the other identified drugs in our future studies.

Matched MeSH terms: Protease Inhibitors
Molecular docking studies of selected medicinal drugs as dengue virus-2 protease inhibitors

Rufaidah Othman, Saiful Anuar Karsani, Rozana Othman, Aida Baharuddin, Ramakrishnan NR, Noorsaadah Abd. Rahman, et al.

Sains Malaysiana, 2017;46:1865-1875.

Dengue is a potentially deadly disease with no effective drug. An in silico molecular docking was performed using Autodock
4.2.6 to investigate the molecular interactions between protease inhibitors, comprising antibiotic derivatives namely
doxycycline (3), rolitetracycline (5) and a non-steroidal anti-inflammatory drug (NSAID), meclofenamic acid (4), against
the NS2B-NS3 protease from dengue virus-2 (DENV-2). The non-competitive inhibitor (3) showed lower binding energy
(-5.15 kcal/mol) than the predicted competitive inhibitors 4 and 5 (-3.64 and -3.21 kcal/mol, respectively). Structural
analyses showed compound 3 that bound to a specific allosteric site, interacted with Lys74, a significant amino acid
residue bonded to one of the catalytic triad, Asp75. Compounds 4 and 5 showed direct binding with two of the catalytic
triad, His51 and Ser135, hence, predicted to be competitive inhibitors.

Matched MeSH terms: Protease Inhibitors
Fulltext Identification of natural antimicrobial agents to treat dengue infection: In vitro analysis of latarcin peptide activity against dengue virus

Rothan HA, Bahrani H, Rahman NA, Yusof R

BMC Microbiol, 2014;14:140.
PMID: 24885331 DOI: 10.1186/1471-2180-14-140

Although there have been considerable advances in the study of dengue virus, no vaccines or anti-dengue drugs are currently available for humans. Therefore, new approaches are necessary for the development of potent anti-dengue drugs. Natural antimicrobial peptides (AMPs) with potent antiviral activities are potential hits-to-leads for antiviral drug discovery. We performed this study to identify and characterise the inhibitory potential of the latarcin peptide (Ltc 1, SMWSGMWRRKLKKLRNALKKKLKGE) against dengue virus replication in infected cells.

Matched MeSH terms: Protease Inhibitors/isolation & purification; Protease Inhibitors/pharmacology
Fulltext Screening of antiviral activities in medicinal plants extracts against dengue virus using dengue NS2B-NS3 protease assay

Rothan HA, Zulqarnain M, Ammar YA, Tan EC, Rahman NA, Yusof R

Trop Biomed, 2014 Jun;31(2):286-96.
PMID: 25134897 MyJurnal

Dengue virus infects millions of people worldwide and there is no vaccine or anti-dengue therapeutic available. Screening large numbers of medicinal plants for anti-dengue activities is an alternative strategy in order to find the potent therapeutic compounds. Therefore, this study was designed to identify anti-dengue activities in nineteen medicinal plant extracts that are used in traditional medicine. Local medicinal plants Vernonia cinerea, Hemigraphis reptans, Hedyotis auricularia, Laurentia longiflora, Tridax procumbers and Senna angustifolia were used in this study. The highest inhibitory activates against dengue NS2B-NS3pro was observed in ethanolic extract of S. angustifolia leaves, methanolic extract of V. cinerea leaves and ethanol extract of T. procumbens stems. These findings were further verified by in vitro viral inhibition assay. Methanolic extract of V. cinerea leaves, ethanol extract of T. procumbens stems and at less extent ethanolic extract of S. angustifolia leaves were able to maintain the normal morphology of DENV2-infected Vero cells without causing much cytopathic effects (CPE). The percentage of viral inhibition of V. cinerea and T. procumbens extracts were significantly higher than S. angustifolia extract as measured by plaque formation assay and RT-qPCR. In conclusion, The outcome of this study showed that the methanolic extract of V. cinerea leaves and ethanol extract of T. procumbens stems possessed high inhibitory activates against dengue virus that worth more investigation.

Matched MeSH terms: Protease Inhibitors/isolation & purification; Protease Inhibitors/pharmacology*; Protease Inhibitors/toxicity
Virological failure and HIV drug resistance among adults living with HIV on second-line antiretroviral therapy in the Asia-Pacific

Ross J, Jiamsakul A, Kumarasamy N, Azwa I, Merati TP, Do CD, et al.

HIV Med, 2021 Mar;22(3):201-211.
PMID: 33151020 DOI: 10.1111/hiv.13006

OBJECTIVES: To assess second-line antiretroviral therapy (ART) virological failure and HIV drug resistance-associated mutations (RAMs), in support of third-line regimen planning in Asia.
METHODS: Adults > 18 years of age on second-line ART for ≥ 6 months were eligible. Cross-sectional data on HIV viral load (VL) and genotypic resistance testing were collected or testing was conducted between July 2015 and May 2017 at 12 Asia-Pacific sites. Virological failure (VF) was defined as VL > 1000 copies/mL with a second VL > 1000 copies/mL within 3-6 months. FASTA files were submitted to Stanford University HIV Drug Resistance Database and RAMs were compared against the IAS-USA 2019 mutations list. VF risk factors were analysed using logistic regression.
RESULTS: Of 1378 patients, 74% were male and 70% acquired HIV through heterosexual exposure. At second-line switch, median [interquartile range (IQR)] age was 37 (32-42) years and median (IQR) CD4 count was 103 (43.5-229.5) cells/µL; 93% received regimens with boosted protease inhibitors (PIs). Median duration on second line was 3 years. Among 101 patients (7%) with VF, CD4 count > 200 cells/µL at switch [odds ratio (OR) = 0.36, 95% confidence interval (CI): 0.17-0.77 vs. CD4 ≤ 50) and HIV exposure through male-male sex (OR = 0.32, 95% CI: 0.17-0.64 vs. heterosexual) or injecting drug use (OR = 0.24, 95% CI: 0.12-0.49) were associated with reduced VF. Of 41 (41%) patients with resistance data, 80% had at least one RAM to nonnucleoside reverse transcriptase inhibitors (NNRTIs), 63% to NRTIs, and 35% to PIs. Of those with PI RAMs, 71% had two or more.
CONCLUSIONS: There were low proportions with VF and significant RAMs in our cohort, reflecting the durability of current second-line regimens.

Matched MeSH terms: Protease Inhibitors
Evaluation of potential bacterial protease inhibitor properties of selected hydroxyquinoline derivatives: an in silico docking and molecular dynamics simulation approach

Riaz F, Hossain MS, Roney M, Ali Y, Qureshi S, Muhammad R, et al.

J Biomol Struct Dyn, 2023 Nov;41(19):9756-9769.
PMID: 36399018 DOI: 10.1080/07391102.2022.2146200

Antimicrobial drug resistance (AMR) is a severe global threat to public health. The increasing emergence of drug-resistant bacteria requires the discovery of novel antibacterial agents. Quinoline derivatives have previously been reported to exhibit antimalarial, antiviral, antitumor, antiulcer, antioxidant and, most interestingly, antibacterial properties. In this study, we evaluated the binding affinity of three newly designed hydroxyquinolines derived from sulfanilamide (1), 4-amino benzoic acid (2) and sulfanilic acid (3) towards five bacterial protein targets (PDB ID: 1JIJ, 3VOB, 1ZI0, 6F86, 4CJN). The three derivatives were designed considering the amino acid residues identified at the active site of each protein involved in the binding of each co-crystallized ligand and drug-likeness properties. The ligands displayed binding energy values with the target proteins ranging from -2.17 to -8.45 kcal/mol. Compounds (1) and (3) showed the best binding scores towards 1ZI0/3VOB and 1JIJ/4CJN, respectively, which may serve as new antibiotic scaffolds. Our in silico results suggest that sulfanilamide (1) or sulfanilic acid (3) hydroxyquinoline derivatives have the potential to be developed as bacterial inhibitors, particularly MRSA inhibitors. But before that, it must go through the proper preclinical and clinical trials for further scientific validation. Further experimental studies are warranted to explore the antibacterial potential of these compounds through preclinical and clinical studies.Communicated by Ramaswamy H. Sarma.

Matched MeSH terms: Protease Inhibitors
Development and validation of a rapid ultra high performance liquid chromatography with tandem mass spectrometry method for the simultaneous determination of darunavir, ritonavir, and tenofovir in human plasma: Application to human pharmacokinetics

Reddy AV, Jaafar J, Aris AB, Majid ZA, Umar K, Talib J, et al.

J Sep Sci, 2015 Aug;38(15):2580-7.
PMID: 25989063 DOI: 10.1002/jssc.201500250

A sensitive ultra high performance liquid chromatography with tandem mass spectrometry method was developed for the simultaneous determination of darunavir, ritonavir and tenofovir in human plasma. Sample preparation involved a simple liquid-liquid extraction using 200 μL of human plasma extracted with methyl tert-butyl ether for three analytes and internal standard. The separation was accomplished on an Acquity UPLC BEH C18 (50 mm x 2.1 mm, 1.7 μm) analytical column using gradient elution of acetonitrile/methanol (80:20, v/v) and 5.0 mM ammonium acetate containing 0.01% formic acid at a flow rate of 0.4 mL/min. The linearity of the method ranged between 20.0 and 12 000 ng/mL for darunavir, 2.0 and 2280 ng/mL for ritonavir, and 14.0 and 1600 ng/mL for tenofovir using 200 μL of plasma. The method was completely validated for its selectivity, sensitivity, linearity, precision and accuracy, recovery, matrix effect, stability, and dilution integrity. The extraction recoveries were consistent and ranged between 79.91 and 90.04% for all three analytes and internal standard. The method exhibited good intra-day and inter-day precision between 1.78 and 6.27%. Finally the method was successfully applied for human pharmacokinetic study in eight healthy male volunteers after the oral administration of 600 mg darunavir along with 100 mg ritonavir and 100 mg tenofovir as boosters.

Matched MeSH terms: HIV Protease Inhibitors/blood*; HIV Protease Inhibitors/pharmacokinetics
Fulltext Role of α-helical structure in organic solvent-activated homodimer of elastase strain K

Rahman RN, Salleh AB, Basri M, Wong CF

Int J Mol Sci, 2011;12(9):5797-814.
PMID: 22016627 DOI: 10.3390/ijms12095797

Recombinant elastase strain K overexpressed from E. coli KRX/pCon2(3) was purified to homogeneity by a combination of hydrophobic interaction chromatography and ion exchange chromatography, with a final yield of 48% and a 25-fold increase in specific activity. The purified protein had exhibited a first ever reported homodimer size of 65 kDa by SDS-PAGE and MALDI-TOF, a size which is totally distinct from that of typically reported 33 kDa monomer from P. aeruginosa. The organic solvent stability experiment had demonstrated a stability pattern which completely opposed the rules laid out in previous reports in which activity stability and enhancement were observed in hydrophilic organic solvents such as DMSO, methanol, ethanol and 1-propanol. The high stability and enhancement of the enzyme in hydrophilic solvents were explained from the view of alteration in secondary structures. Elastinolytic activation and stability were observed in 25 and 50% of methanol, respectively, despite slight reduction in α-helical structure caused upon the addition of the solvent. Further characterization experiments had postulated great stability and enhancement of elastase strain K in broad range of temperatures, pHs, metal ions, surfactants, denaturing agents and substrate specificity, indicating its potential application in detergent formulation.

Matched MeSH terms: Protease Inhibitors/pharmacology
Fulltext Prevalence and Structure of HIV-1 Drug Resistance to Antiretrovirals in the Volga Federal District in 2008-2019

Peksheva O, Kuzovatova E, Parfenova O, Zaytseva N

Viruses, 2022 Aug 27;14(9).
PMID: 36146704 DOI: 10.3390/v14091898

The increasing number of HIV-infected people who are receiving ART, including those with low adherence, is causing the spread of HIV drug resistance (DR). A total of 1396 plasma samples obtained from treatment-experienced patients from the Volga federal district (VFD), Russia, were examined to investigate HIV DR occurrence. The time periods 2008−2015 and 2016−2019 were compared. Fragmentary Sanger sequencing was employed to identify HIV resistance to reverse transcriptase inhibitors (RTIs) and protease inhibitors (PIs) using an ABI 3500XL genetic analyzer, a ViroSeq™ HIV-1 genotyping system (Alameda, CA, USA) and AmpliSense HIV-Resist-Seq reagent kits (Moscow, Russia). In 2016−2019, HIV DR was detected significantly more often than in 2008−2015 (p < 0.01). Mutations to RTIs retained leading positions in the structure of DR. Frequencies of resistance mutations to nucleoside and non-nucleoside RTIs (NRTIs and NNRTIs) in the spectra of detected mutations show no significant differences. Resistance to NRTIs after 2016 began to be registered more often as a part of multidrug resistance (MDR), as opposed to resistance to a single class of antiretrovirals. The frequency of DR mutations to PIs was low, both before and after 2016 (7.9% and 6.1% in the spectrum, respectively, p > 0.05). MDR registration rate became significantly higher from 2008 to 2019 (17.1% to 72.7% of patients, respectively, p < 0.01). M184V was the dominant replacement in all the years of study. A significant increase in the frequency of K65R replacement was revealed. The prevalence of integrase strand transfer inhibitor (INSTI) resistance mutations remains to be investigated.

Matched MeSH terms: Protease Inhibitors/pharmacology
Docking of noncompetitive inhibitors into dengue virus type 2 protease: understanding the interactions with allosteric binding sites

Othman R, Kiat TS, Khalid N, Yusof R, Newhouse EI, Newhouse JS, et al.

J Chem Inf Model, 2008 Aug;48(8):1582-91.
PMID: 18656912 DOI: 10.1021/ci700388k

A group of flavanones and their chalcones, isolated from Boesenbergia rotunda L., were previously reported to show varying degrees of noncompetitive inhibitory activities toward Dengue virus type 2 (Den2) protease. Results obtained from automated docking studies are in agreement with experimental data in which the ligands were shown to bind to sites other than the active site of the protease. The calculated K(i) values are very small, indicating that the ligands bind quite well to the allosteric binding site. Greater inhibition by pinostrobin, compared to the other compounds, can be explained by H-bonding interaction with the backbone carbonyl of Lys74, which is bonded to Asp75 (one of the catalytic triad residues). In addition, structure-activity relationship analysis yields structural information that may be useful for designing more effective therapeutic drugs against dengue virus infections.

Matched MeSH terms: Protease Inhibitors/pharmacology*; Protease Inhibitors/chemistry*

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