TY - JOUR
T1 - Analysis of quaternary structure of a [LDH-like] malate dehydrogenase of Plasmodium falciparum with oligomeric mutants
AU - Pradhan, Anupam
AU - Mukherjee, Prasenjit
AU - Tripathi, Abhai K.
AU - Avery, Mitchell A.
AU - Walker, Larry A.
AU - Tekwani, Babu L.
N1 - Funding Information:
Acknowledgements This work was supported by CDC cooperative agreement U01/CI 000211-01. We thank Dr. Prashant Desai for his sincere help and advice in molecular modeling studies. NCNPR also gets financial support from United States Department of Agriculture-Agricultural Research Services (USDA-ARS) through a cooperative scientific agreement no. 58-6408-2-0009.
PY - 2009
Y1 - 2009
N2 - 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.
AB - 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.
KW - 3-Acetylpyridine adenine dinucleotide
KW - Lactate dehydrogenase
KW - Malaria
KW - Malate dehydrogenase
KW - Plasmodium falciparum
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U2 - 10.1007/s11010-009-0028-2
DO - 10.1007/s11010-009-0028-2
M3 - Article
C2 - 19184366
AN - SCOPUS:64249170464
SN - 0300-8177
VL - 325
SP - 141
EP - 148
JO - Molecular and Cellular Biochemistry
JF - Molecular and Cellular Biochemistry
IS - 1-2
ER -