scholarly journals Role of Plasmodium falciparum Digestive Vacuole Plasmepsins in the Specificity and Antimalarial Mode of Action of Cysteine and Aspartic Protease Inhibitors

2009 ◽  
Vol 53 (12) ◽  
pp. 4968-4978 ◽  
Author(s):  
Pedro A. Moura ◽  
John B. Dame ◽  
David A. Fidock
Keyword(s):  
Plasmodium Falciparum ◽  
Protease Inhibitors ◽  
Mode Of Action ◽  
Antimalarial Drug ◽  
Cysteine Proteases ◽  
Aspartic Protease ◽  
Parasite Line ◽  
Digestive Vacuole ◽  
Aspartic Proteases ◽  
Wide Range

ABSTRACT Hemoglobin (Hb) degradation is essential for the growth of the intraerythrocytic stages of malarial parasites. This process, which occurs inside an acidic digestive vacuole (DV), is thought to involve the action of four aspartic proteases, termed plasmepsins (PMs). These enzymes have received considerable attention as potential antimalarial drug targets. Leveraging the availability of a set of PM-knockout lines generated in Plasmodium falciparum, we report here that a wide range of previously characterized or novel aspartic protease inhibitors exert their antimalarial activities independently of their effect on the DV PMs. We also assayed compounds previously shown to inhibit cysteine proteases residing in the DV. The most striking observation was a ninefold increase in the potency of the calpain inhibitor N-acetyl-leucinyl-leucinyl-norleucinal (ALLN) against parasites lacking all four DV PMs. Genetic ablation of PM III or PM IV also decreased the level of parasite resistance to the β-hematin binding antimalarial chloroquine. On the basis of the findings of drug susceptibility and isobologram assays, as well as the findings of studies of the inhibition of Hb degradation, morphological analyses, and stage specificity, we conclude that the DV PMs and falcipain cysteine proteases act cooperatively in Hb hydrolysis. We also identify several aspartic protease inhibitors, designed to target DV PMs, which appear to act on alternative targets early in the intraerythrocytic life cycle. These include the potent diphenylurea compound GB-III-32, which was found to be fourfold less potent against a P. falciparum line overexpressing plasmepsin X than against the parental nontransformed parasite line. The identification of the mode of action of these inhibitors will be important for future antimalarial drug discovery efforts focusing on aspartic proteases.

Kinetic analysis of plasmepsins I and II, aspartic proteases of the Plasmodium falciparum digestive vacuole

1996 ◽  
Vol 79 (1) ◽  
pp. 71-78 ◽  
Author(s):  
Kathryn E. Luker ◽  
Susan E. Francis ◽  
Ilya Y. Gluzman ◽  
Daniel E. Goldberg
Keyword(s):  
Plasmodium Falciparum ◽  
Kinetic Analysis ◽  
Digestive Vacuole ◽  
Aspartic Proteases

scholarly journals Hemoglobin degradation in the human malaria pathogen Plasmodium falciparum: a catabolic pathway initiated by a specific aspartic protease.

1991 ◽  
Vol 173 (4) ◽  
pp. 961-969 ◽  
Author(s):  
D E Goldberg ◽  
A F Slater ◽  
R Beavis ◽  
B Chait ◽  
A Cerami ◽  
...  
Keyword(s):  
Laser Desorption ◽  
Aspartic Protease ◽  
Digestive Vacuole ◽  
Catabolic Pathway ◽  
Nutrient Source ◽  
Aspartic Proteases ◽  
Laser Desorption Mass Spectrometry ◽  
Proteolytic Action ◽  
Hemoglobin Degradation

Hemoglobin is an important nutrient source for intraerythrocytic malaria organisms. Its catabolism occurs in an acidic digestive vacuole. Our previous studies suggested that an aspartic protease plays a key role in the degradative process. We have now isolated this enzyme and defined its role in the hemoglobinolytic pathway. Laser desorption mass spectrometry was used to analyze the proteolytic action of the purified protease. The enzyme has a remarkably stringent specificity towards native hemoglobin, making a single cleavage between alpha 33Phe and 34Leu. This scission is in the hemoglobin hinge region, unraveling the molecule and exposing other sites for proteolysis. The protease is inhibited by pepstatin and has NH2-terminal homology to mammalian aspartic proteases. Isolated digestive vacuoles make a pepstatin-inhibitable cleavage identical to that of the purified enzyme. The pivotal role of this aspartic hemoglobinase in initiating hemoglobin degradation in the malaria parasite digestive vacuoles is demonstrated.

scholarly journals Comparison of Efficacies of Cysteine Protease Inhibitors against Five Strains of Plasmodium falciparum

2001 ◽  
Vol 45 (3) ◽  
pp. 949-951 ◽  
Author(s):  
Ajay Singh ◽  
Philip J. Rosenthal
Keyword(s):  
Plasmodium Falciparum ◽  
Protease Inhibitors ◽  
Cysteine Protease ◽  
Antimalarial Drug ◽  
Drug Target ◽  
Antimalarial Drugs ◽  
Cross Resistance ◽  
Cysteine Protease Inhibitors ◽  
Antimalarial Agents ◽  
Parasite Strains

ABSTRACT Falcipain-2, a cysteine protease and essential hemoglobinase ofPlasmodium falciparum, is a potential antimalarial drug target. We compared the falcipain-2 sequences and sensitivities to cysteine protease inhibitors of five parasite strains that differ markedly in sensitivity to established antimalarial drugs. The sequence of falcipain-2 was highly conserved, and the sensitivities of all of the strains to falcipain-2 inhibitors were very similar. Thus, cross-resistance between cysteine protease inhibitors and other antimalarial agents is not expected in parasites that are now circulating and falcipain-2 remains a promising chemotherapeutic target.

scholarly journals Why re-purposing HIV drugs Lopinavir/ritonavir to inhibit the SARS-Cov2 protease probably wont work - but re-purposing Ribavirin might since it has a very similar binding site within the RNA-polymerase

2020 ◽  
Author(s):  
Sandeep Chakraborty
Keyword(s):  
Rna Polymerase ◽  
Binding Site ◽  
Protease Inhibitors ◽  
Cysteine Protease ◽  
Cysteine Proteases ◽  
Aspartic Protease ◽  
Catalytic Site ◽  
Hiv Protease ◽  
Hiv Protease Inhibitors ◽  
Hiv Drugs

A trial of Lopinavir/Ritonavir in adults hospitalized with severe Covid-19 has not shown significant dif- ference [1]. This is not surprising considering that the HIV aspartic protease - which Lopinavir/Ritonavir inhibit (Table 1) - is quite different from the cysteine proteases in SARS-Cov2.A review explains this well - ‘it is debatable whether HIV protease inhibitors could effectively inhibit the 3-chymotrypsin-like and papain-like proteases of 2019-nCoV. HIV protease belongs to the aspartic protease family, whereas the two coronavirus proteases are from the cysteine protease family. Furthermore, HIV protease inhibitors were specifically optimized to fit the C2 symmetry in the catalytic site of the HIV protease dimer, but this C2-symmetric pocket is absent in coronavirus proteases. If HIV protease inhibitors alter host pathways to indirectly interfere with coronavirus infections, their potency remains a concern.’ [2].However, using known structures of the SARS-Cov2, one can dock molecules, and thus re-purpose existing drugs.

scholarly journals Defense against own arms: staphylococcal cysteine proteases and their inhibitors.

2003 ◽  
Vol 50 (3) ◽  
pp. 715-724 ◽  
Author(s):  
Grzegorz Dubin
Keyword(s):  
Staphylococcus Aureus ◽  
Protease Inhibitors ◽  
Current Knowledge ◽  
Cysteine Proteases ◽  
Infection Process ◽  
Secreted Proteins ◽  
Human Pathogen ◽  
Cysteine Protease Inhibitors ◽  
Wide Range

Staphylococcus aureus is a human pathogen causing a wide range of diseases. Most staphylococcal infections, unlike those caused by other bacteria are not toxigenic and very little is known about their pathogenesis. It has been proposed that a core of secreted proteins common to many infectious strains is responsible for colonization and infection. Among those proteins several proteases are present and over the years many different functions in the infection process have been attributed to them. However, little direct, in vivo data has been presented. Two cysteine proteases, staphopain A (ScpA) and staphopain B (SspB) are important members of this group of enzymes. Recently, two cysteine protease inhibitors, staphostatin A and staphostatin B (ScpB and SspC, respectively) were described in S. aureus shedding new light on the complexity of the processes involving the two proteases. The scope of this review is to summarize current knowledge on the network of staphylococcal cysteine proteases and their inhibitors in view of their possible role as virulence factors.

scholarly journals Molecular Characterization of Plasmodium Falciparum DNA-3-Methyladenine Glycosylase

2020 ◽  
Author(s):  
Nattapon Pinthong ◽  
Paviga Limudomporn ◽  
Jitlada Vasuvat ◽  
Poom Adisakwattana ◽  
Pongruj Rattaprasert ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Antimalarial Drug ◽  
Specific Activity ◽  
Cloning And Expression ◽  
Parasite Development ◽  
Potential Candidate ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Wide Range ◽  
Human Counterpart

Abstract Background The emergence of artemisinin-resistant malaria parasite highlights the need for novel drugs and their targets. Alkylation in purine bases can hinder DNA replication if remained unsolved would eventually resulting in cell death. DNA-3-methyladenine glycosylase is an enzyme responsible for the repair of those alkylated lesions. Based on the AT-rich genome of Plasmodium falciparum and unexplored Plasmodium falciparum DNA-3-methyladenine glycosylase (PfMAG), therefore PfMAG should be characterized for its potential candidate for antimalarial drug development.Methods Bioinformatics analysis of PfMAG was performed. The native PfMAG from crude extract of chloroquine and pyrimethamine resistant Plasmodium falciparum strain K1 was partially purified using three columns. The existence of PfMAG activity leads to the cloning and expression of PfMAG for further characterization. The PfMAG was amplified, cloned to expression vector (pBAD202/D-TOPO), and expressed in Escherichia coli. The molecular weight of recombinant PfMAG was analyzed by SDS-PAGE and Western blot. Both functional and biochemical properties of the recombinant enzyme were characterized.Results PfMAG activity was most prominent in schizont. Native PfMAG was partially purified with a specific activity of 147.36 units/mg protein. The DNA sequence of amplified PfMAG showed an insertion of three nucleotides coding for asparagine compared to strain 3D7 and only 16% similarity compared to the human enzyme was observed. After cloning, the 74-kDa recombinant PfMAG was expressed and identified. PfMAG showed a larger size than its human counterpart twice. PfMAG preferred a double-stranded DNA substrate. Glycosylase activity was detected in a broad range of pH 5–8. The quite narrow optimal salt concentration was observed between 100–200 mM NaCl, whereas 250 mM NaCl reduces its activity. Divalent cations are not required for its glycosylase activity; on the contrary, they inhibited glycosylase activity in a concentration-dependent manner.Conclusion PfMAG activity increases according to parasite development. Native PfMAG was partially purified, the recombinant PfMAG was successfully expressed and characterized. An insertion of AAT coding for asparagine was found compared with that of strain 3D7. PfMAG differs from the human counterpart in a twice larger size and a wide range of optimal pH. Results obtained from this study will be a benefit for exploring and investigating of candidate targets toward antimalarial drug design in the future.

scholarly journals Antiviral Drug Discovery: Norovirus Proteases and Development of Inhibitors

Viruses ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 197 ◽  
Author(s):  
Kyeong-Ok Chang ◽  
Yunjeong Kim ◽  
Scott Lovell ◽  
Athri Rathnayake ◽  
William Groutas
Keyword(s):  
Protease Inhibitors ◽  
Antiviral Agents ◽  
Antiviral Drug ◽  
Cysteine Proteases ◽  
Life Forms ◽  
Biological Processes ◽  
Macrocyclic Compounds ◽  
Viral Proteases ◽  
Wide Range ◽  
Immunodeficiency Virus

Proteases are a major enzyme group playing important roles in a wide variety of biological processes in life forms ranging from viruses to mammalians. The aberrant activity of proteases can lead to various diseases; consequently, host proteases have been the focus of intense investigation as potential therapeutic targets. A wide range of viruses encode proteases which play an essential role in viral replication and, therefore, constitute attractive targets for the development of antiviral therapeutics. There are numerous examples of successful drug development targeting cellular and viral proteases, including antivirals against human immunodeficiency virus and hepatitis C virus. Most FDA-approved antiviral agents are peptidomimetics and macrocyclic compounds that interact with the active site of a targeted protease. Norovirus proteases are cysteine proteases that contain a chymotrypsin-like fold in their 3D structures. This review focuses on our group’s efforts related to the development of norovirus protease inhibitors as potential anti-norovirus therapeutics. These protease inhibitors are rationally designed transition-state inhibitors encompassing dipeptidyl, tripeptidyl and macrocyclic compounds. Highly effective inhibitors validated in X-ray co-crystallization, enzyme and cell-based assays, as well as an animal model, were generated by launching an optimization campaign utilizing the initial hit compounds. A prodrug approach was also explored to improve the pharmacokinetics (PK) of the identified inhibitors.

Antimalarial Synergy of Cysteine and Aspartic Protease Inhibitors

1998 ◽  
Vol 42 (9) ◽  
pp. 2254-2258 ◽  
Author(s):  
Andrey Semenov ◽  
Jed E. Olson ◽  
Philip J. Rosenthal
Keyword(s):  
Amino Acids ◽  
Protease Inhibitors ◽  
Synergistic Effects ◽  
Aspartic Protease ◽  
Aspartic Proteases ◽  
Synergistic Inhibition ◽  
Antimalarial Therapy ◽  
Plasmepsin Ii ◽  
Hemoglobin Degradation ◽  
Malaria Model

ABSTRACT It has been proposed that the Plasmodium falciparumcysteine protease falcipain and aspartic proteases plasmepsin I and plasmepsin II act cooperatively to hydrolyze hemoglobin as a source of amino acids for erythrocytic parasites. Inhibitors of each of these proteases have potent antimalarial effects. We have now evaluated the antimalarial effects of combinations of cysteine and aspartic protease inhibitors. When incubated with cultured P. falciparumparasites, cysteine and aspartic protease inhibitors exhibited synergistic effects in blocking parasite metabolism and development. The inhibitors also demonstrated apparent synergistic inhibition of plasmodial hemoglobin degradation both in culture and in a murine malaria model. When evaluated for the treatment of murine malaria, a combination of cysteine and aspartic protease inhibitors was much more effective than higher concentrations of either compound used alone. These results support a model whereby plasmodial cysteine and aspartic proteases participate in the degradation of hemoglobin, and they suggest that combination antimalarial therapy with inhibitors of the two classes of proteases is worthy of further study.

scholarly journals Synergistic Interactions of the Antiretroviral Protease Inhibitors Saquinavir and Ritonavir with Chloroquine and Mefloquine against Plasmodium falciparum In Vitro

2006 ◽  
Vol 51 (2) ◽  
pp. 759-762 ◽  
Author(s):  
T. S. Skinner-Adams ◽  
K. T. Andrews ◽  
L. Melville ◽  
J. McCarthy ◽  
D. L. Gardiner
Keyword(s):  
Human Immunodeficiency Virus ◽  
Plasmodium Falciparum ◽  
Protease Inhibitors ◽  
Antimalarial Activity ◽  
Digestive Vacuole ◽  
Synergistic Interactions ◽  
Human Immunodeficiency Virus Protease ◽  
Immunodeficiency Virus ◽  
Pepstatin A

ABSTRACT The antimalarial activity of several antiretroviral protease inhibitor combinations was investigated. Data demonstrate that ritonavir and saquinavir behave synergistically with chloroquine and mefloquine. These data, and interactions with pepstatin-A, E-64, and bestatin, suggest that human immunodeficiency virus protease inhibitors do not target digestive-vacuole plasmepsins.

Template-Mediated Biomineralization of Hemozoin

1999 ◽  
Vol 599 ◽  
Author(s):  
David W. Wright ◽  
James Ziegler
Keyword(s):  
Plasmodium Falciparum ◽  
Tandem Repeat ◽  
Antimalarial Drug ◽  
Malaria Parasite ◽  
Natural Substrate ◽  
Digestive Vacuole ◽  
Metal Free ◽  
Peptide Dendrimers ◽  
Free Heme ◽  
Detoxification Pathway

AbstractA critical target for the development of new antimalarial treatments is the detoxification pathway of free heme released during the catabolism of host hemoglobin in the digestive vacuole of the malaria parasite Plasmodium falciparum. We have synthesized and examined two peptide dendrimers (BNT I and II) based on the tandem repeat motif of HRP II from P. falciparum for their abilities to both bind heme substrates and to form the critical detoxification polymer hemozoin. Each substrate was capable of binding significant amounts of the natural substrate Fe(III)PPIX along with other substrates such as Zn(II)PPIX and the metal free PPIX. Further, it was shown that the dendrimeric BNT I and II were capable of supporting the aggregation of hemozoin and that this process could be inhibited by the known antimalarial drug, chloroquine.

Sign in / Sign up

Export Citation Format

Share Document