Tropical malaria is responsible for more than 1.2 million deaths annually. Severe forms of the disease are mainly caused by the parasite Plasmodium falciparum, transmitted to humans by female Anopheles mosquitoes. Malaria eradication has not been possible due to the lack of vaccines and the parasite's ability to develop resistance to most drugs.
This is an illustration of Anopheles darlingi.
Credit: UC San Diego School of Medicine
The researchers conducted high-throughput screening of nearly 350,000 compounds in the National Institutes of Health's Molecular Libraries Small Molecule Repository (MLSMR) to identify compounds that inhibit an enzyme which plays an important role in parasite development: Plasmodium falciparum glucose-6-phosphate dehydrogenase (PfG6PD) is essential for proliferating and propagating P. falciparum.
"The enzyme G6PD catalyzes an initial step in a process that protects the malaria parasite from oxidative stress in red blood cells, creating an environment in which the parasite survives," said senior author Lars Bode, PhD, assistant professor in the UCSD Department of Pediatrics, Division of Neonatology and the Division of Gastroenterology, Hepatology and Nutrition. People with a natural deficiency in this enzyme are protected from malaria and its deadly symptoms, an observation that triggered the reported research.
The parasitic form of the enzyme (PfG6PD) is what contributes the majority of G6PD activity in infected red blood cells. Because the parasite lives in the blood of a malaria-infected person, the scientists aimed at identifying compounds that inhibit the parasitic form but not the human form of the enzyme. "We didn't want to interfere with the human form of the enzyme and risk potential side effects," Bode explained.
Scientific testing had previously been limited by a lack of recombinant PfG6PD. Team members in the lab of Katja Becker, PhD, at the Interdisciplinary Research Center at Justus-Liebig-University in Giessen, Germany produced the first complete and functional recombinant PfG6PD, and researchers led by Anthony Pinkerton, PhD, at Sanford-Burnham Medical Research Institute used it to identify the lead compound resulting from their efforts, ML276.
ML276 represents the first reported selective PfG6PD inhibitor, which stops the growth of malaria parasites in cultured red blood cells – even those parasites that developed resistance to currently available drugs. "ML276 is a very promising basis for future drug design of new anti-malarial therapeutics," said Bode.
Contributors to the study include Janina Preuss, UC San Diego, Justus-Liebig-University and Sanford-Burnham Medical Research Institute; Esther Jortzik, Stefan Rahlfs and Katja Becker, Justus-Liebig-University; Patrick Maloney, Satyamaheshwar Peddibhotla, Paul Hershberger, Eliot Sugarman, Becky Hood, Eigo Suyama, Kevin Nguyen, Stefan Vasile, Arianna Mangravita-Novo, Michael Vicchiarelli, Danielle McAnally, Layton H. Smith. Gregory P. Roth, Michael P. Hedrick, Palak Gosalia, Monika Milewski, Yujie Linda Li, Eduard Sergienko, Jena Diwan, Thomas D.Y. Chung, and Anthony B. Pinkerton, Sanford-Burnham.
The study was supported by the National Institutes of Health (1R21AI082434), the Deutsche Forschungsgemeinschaft, and an NIH Molecular Libraries grant (U54 HG005033) to the Conrad Prebys Center for Chemical Genomics at Sanford Burnham Medical Research Institute, one of the comprehensive centers of the NIH Molecular Libraries Probe Production Centers Network (MLPCN).
Debra Kain | EurekAlert!
New image of a cancer-related enzyme in action helps explain gene regulation
05.06.2020 | Penn State
Protecting the Neuronal Architecture
05.06.2020 | Universität Heidelberg
Humans rely dominantly on their eyesight. Losing vision means not being able to read, recognize faces or find objects. Macular degeneration is one of the major...
In meningococci, the RNA-binding protein ProQ plays a major role. Together with RNA molecules, it regulates processes that are important for pathogenic properties of the bacteria.
Meningococci are bacteria that can cause life-threatening meningitis and sepsis. These pathogens use a small protein with a large impact: The RNA-binding...
An analysis of more than 200,000 spiral galaxies has revealed unexpected links between spin directions of galaxies, and the structure formed by these links...
Two prominent X-ray emission lines of highly charged iron have puzzled astrophysicists for decades: their measured and calculated brightness ratios always disagree. This hinders good determinations of plasma temperatures and densities. New, careful high-precision measurements, together with top-level calculations now exclude all hitherto proposed explanations for this discrepancy, and thus deepen the problem.
Hot astrophysical plasmas fill the intergalactic space, and brightly shine in stellar coronae, active galactic nuclei, and supernova remnants. They contain...
In living cells, enzymes drive biochemical metabolic processes enabling reactions to take place efficiently. It is this very ability which allows them to be used as catalysts in biotechnology, for example to create chemical products such as pharmaceutics. Researchers now identified an enzyme that, when illuminated with blue light, becomes catalytically active and initiates a reaction that was previously unknown in enzymatics. The study was published in "Nature Communications".
Enzymes: they are the central drivers for biochemical metabolic processes in every living cell, enabling reactions to take place efficiently. It is this very...
19.05.2020 | Event News
07.04.2020 | Event News
06.04.2020 | Event News
05.06.2020 | Life Sciences
05.06.2020 | Physics and Astronomy
05.06.2020 | Life Sciences