Oligomeric interfaces as a tool in drug discovery: Specific interference with activity of malate dehydrogenase of Plasmodium falciparum in vitro

Author(s)

Lunev, Sergey ^[1] ; Butzloff, Sabine ^[2] ; Romero, Atilio R. ^[1] ; Linzke, Marleen ^[3] ; Batista, Fernando A. ^[1] ; Meissner, Kamila A. ^[3] ; Mueller, Ingrid B. ^[2] ; Adawy, Alaa ^[1] ; Wrenger, Carsten ^[3] ; Groves, Matthew R. ^[1]

Affiliation

^[1] Univ Groningen, Dept Pharm, Drug Design XB20, Struct Biol Unit, Groningen - Netherlands

^[2] Bernhard Nocht Inst Trop Med, Hamburg - Germany

^[3] Univ Sao Paulo, Inst Biomed Sci, Dept Parasitol, Unit Drug Discovery, Sao Paulo - Brazil

• Document type: Journal article
• Source: PLoS One; v. 13, n. 4 APR 25 2018.
• Web of Science Citations: 2

Abstract

Malaria remains a major threat to human health, as strains resistant to current therapeutics are discovered. Efforts in finding new drug targets are hampered by the lack of sufficiently specific tools to provide target validation prior to initiating expensive drug discovery projects. Thus, new approaches that can rapidly enable drug target validation are of significant interest. In this manuscript we present the crystal structure of malate dehydrogenase from Plasmodium falciparum (PfMDH) at 2.4 angstrom resolution and structure-based mutagenic experiments interfering with the inter-oligomeric interactions of the enzyme. We report decreased thermal stability, significantly decreased specific activity and kinetic parameters of PfMDH mutants upon mutagenic disruption of either oligomeric interface. In contrast, stabilization of one of the interfaces resulted in increased thermal stability, increased substrate/ cofactor affinity and hyperactivity of the enzyme towards malate production at sub-millimolar substrate concentrations. Furthermore, the presented data show that our designed PfMDH mutant could be used as specific inhibitor of the wild type PfMDH activity, as mutated PfMDH copies were shown to be able to self-incorporate into the native assembly upon introduction in vitro, yielding deactivated mutant: wild-type species. These data provide an insight into the role of oligomeric assembly in regulation of PfMDH activity and reveal that recombinant mutants could be used as probe tool for specific modification of the wild type PfMDH activity, thus offering the potential to validate its druggability in vivo without recourse to complex genetics or initial tool compounds. Such tool compounds often lack specificity between host or pathogen proteins (or are toxic in in vivo trials) and result in difficulties in assessing cause and effect D particularly in cases when the enzymes of interest possess close homologs within the human host. Furthermore, our oligomeric interference approach could be used in the future in order to assess druggability of other challenging human pathogen drug targets. (AU)

• FAPESP's process: 16/24790-9 - Dissecting Plasmodium falciparum EXP1/GST2 for xenobiotic defence in glucose-6-phosphate dehydrogenase deficiency
• Grantee: Kamila Anna Meissner
• Support type: Scholarships in Brazil - Post-Doctorate
• FAPESP's process: 15/26722-8 - Drug discovery against human infectious diseases
• Grantee: Carsten Wrenger
• Support type: Research Projects - Thematic Grants
• FAPESP's process: 13/10288-1 - Analysis of the organelle biogenesis in Plasmodium falciparum by live cell imaging
• Grantee: Carsten Wrenger
• Support type: Regular Research Grants
• FAPESP's process: 12/12807-3 - Analysis of the redox status and its effect on the proliferation of Plasmodium falciparum in genetically different erythrocytes
• Grantee: Kamila Anna Meissner
• Support type: Scholarships in Brazil - Doctorate
• FAPESP's process: 14/23330-9 - Morphologic analysis of the apicoplast formation in Plasmodium falciparum
• Grantee: Marleen Linzke
• Support type: Scholarships in Brazil - Doctorate