Analysis of quaternary structure of a [LDH-like] malate dehydrogenase of Plasmodium falciparum with oligomeric mutants

Anupam Pradhan, Prasenjit Mukherjee, Abhai K. Tripathi, Mitchell A. Avery, Larry A. Walker, Babu L. Tekwani

Research output: Contribution to journalArticlepeer-review

Abstract

L-Malate dehydrogenase (PfMDH) from Plasmodium falciparum, the causative agent for the most severe form of malaria, has shown remarkable similarities to L-lactate dehydrogenase (PfLDH). PfMDH is more closely related to [LDH-like] MDHs characterized in archae and other prokaryotes. Initial sequence analysis and identification of critical amino acid residues involved in inter-subunit salt-bridge interactions predict tetrameric structure for PfMDH. The catalytically active recombinant PfMDH was characterized as a tetramer. The enzyme is localized primarily in the parasites cytosol. To gain molecular insights into PfMDH/PfLDH relationships and to understand the quaternary structure of PfMDH, dimers were generated by mutation to the potential salt-bridge interacting sites. The R183A and R214G mutations, which snapped the salt bridges between the dimers and resulted in lower dimeric state, did not affect catalytic properties of the enzyme. The mutant dimers of PfMDH were active equally as the wild-type PfMDH. The studies reveal structure of PfMDH as a dimer of dimers. The tetrameric state of PfMDH was not essential for catalytic functions of the enzyme but may be an evolutionary adaptation for cytosolic localization to support its role in NAD/NADH coupling, an important metabolic function for survival of the malaria parasite.

Original languageEnglish (US)
Pages (from-to)141-148
Number of pages8
JournalMolecular and Cellular Biochemistry
Volume325
Issue number1-2
DOIs
StatePublished - Jan 29 2009

Keywords

  • 3-Acetylpyridine adenine dinucleotide
  • Lactate dehydrogenase
  • Malaria
  • Malate dehydrogenase
  • Plasmodium falciparum

ASJC Scopus subject areas

  • Molecular Biology
  • Clinical Biochemistry
  • Cell Biology

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