Structural Insights into Mechanisms Underlying Mitochondrial and Bacterial Cytochrome c Synthases DOI Creative Commons

Pema L. Childs,

Ethan P. Lowder, Deanna L. Mendez

et al.

Biomolecules, Journal Year: 2024, Volume and Issue: 14(12), P. 1483 - 1483

Published: Nov. 21, 2024

Mitochondrial holocytochrome c synthase (HCCS) is an essential protein in assembling cytochrome (cyt c) of the electron transport system. HCCS binds heme and covalently attaches two vinyls to cysteine thiols cyt CXXCH motif. Human recognizes both c1 complex III (cytochrome bc1). mutated some human diseases it has been investigated recombinantly by mutational, biochemical, reconstitution studies past decade. Here, we employ structural prediction programs (e.g., AlphaFold 3) on its substrates, c. The results, when combined with spectroscopic functional analyses variants, provide insights into basis for binding, apocyt covalent attachment, release holocyt product. Results from vitro purified using peptides as acceptors are consistent modeling substrate binding. Reconstitution provides approach studying assembly, which refractile recombinant vivo (unlike c). We propose a product based cryoEM structures bacterial (CcsBA) active site. analyze kinetoplastid mitochondrial (KCCS), hypothesize molecular evolutionary path endosymbiosis current HCCS.

Language: Английский

Identification of a divalent metal transporter required for cellular iron metabolism in malaria parasites DOI Creative Commons
Kade M. Loveridge, Paul A. Sigala

Proceedings of the National Academy of Sciences, Journal Year: 2024, Volume and Issue: 121(45)

Published: Oct. 28, 2024

Plasmodium falciparum malaria parasites invade and multiply inside red blood cells (RBCs), the most iron-rich compartment in humans. Like all cells, P. requires nutritional iron to support essential metabolic pathways, but critical mechanisms of acquisition trafficking during RBC infection have remained obscure. Parasites internalize liberate massive amounts heme large-scale digestion hemoglobin within an acidic food vacuole (FV) lack a oxygenase release porphyrin-bound iron. Although FV is sequestered into inert hemozoin crystals, prior studies indicate that trace escapes biomineralization susceptible nonenzymatic degradation oxidizing environment labile retain homolog divalent metal transporter 1 (DMT1), known mammalian transporter, its role has not been tested. Our phylogenetic DMT1 (PfDMT1) retains conserved molecular features for transport. We localized this protein membrane defined orientation export-competent topology. Conditional knockdown PfDMT1 expression lethal parasites, which display broad cellular defects iron-dependent functions, including impaired apicoplast biogenesis mitochondrial polarization. are selectively rescued from partial by supplementation with exogenous iron, other metals. These results paradigm whereby gatekeeper blood-stage suggest therapeutic targeting may be potent antimalarial strategy.

Language: Английский

Citations

2
Unraveling mechanisms of iron acquisition in malaria parasites DOI
Kade M. Loveridge, Paul A. Sigala

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: May 14, 2024

ABSTRACT Plasmodium falciparum malaria parasites invade and multiply inside red blood cells (RBCs), the most iron-rich compartment in humans. Like all cells, P. requires nutritional iron to support essential metabolic pathways, but critical mechanisms of acquisition trafficking during RBC infection have remained obscure. Parasites internalize liberate massive amounts heme large-scale digestion hemoglobin within an acidic food vacuole (FV) lack a oxygenase release porphyrin-bound iron. Although FV is sequestered into inert hemozoin crystals, prior studies indicate that trace escapes biomineralization susceptible non-enzymatic degradation oxidizing environment labile retain homolog divalent metal transporter 1 (DMT1), known mammalian transporter, its role has not been tested. Our phylogenetic DMT1 (PfDMT1) retains conserved molecular features for transport. We localized this protein membrane defined orientation export-competent topology. Conditional knockdown PfDMT1 expression lethal parasites, which display broad cellular defects iron-dependent functions, including impaired apicoplast biogenesis mitochondrial polarization. are selectively rescued from partial by supplementation with exogenous iron, other metals. These results paradigm whereby gatekeeper blood-stage suggest therapeutic targeting may be potent antimalarial strategy.

Language: Английский

Citations

1
Malaria parasites require a divergent heme oxygenase for apicoplast gene expression and biogenesis DOI Creative Commons
Amanda Mixon Blackwell, Yasaman Jami‐Alahmadi, Armiyaw S. Nasamu

et al.

eLife, Journal Year: 2024, Volume and Issue: 13

Published: Aug. 27, 2024

Malaria parasites have evolved unusual metabolic adaptations that specialize them for growth within heme-rich human erythrocytes. During blood-stage infection, Plasmodium falciparum internalize and digest abundant host hemoglobin the digestive vacuole. This massive catabolic process generates copious free heme, most of which is biomineralized into inert hemozoin. Parasites also express a divergent heme oxygenase (HO)-like protein (PfHO) lacks key active-site residues has lost canonical HO activity. The cellular role this underpins its retention by been unknown. To unravel PfHO function, we first determined 2.8 Å-resolution X-ray structure revealed highly α-helical fold indicative distant homology. Localization studies unveiled targeting to apicoplast organelle, where it imported undergoes N-terminal processing but retains electropositive transit peptide. We observed conditional knockdown was lethal parasites, died from defective biogenesis impaired isoprenoid-precursor synthesis. Complementation molecular-interaction an essential N-terminus PfHO, selectively associates with genome enzymes involved in nucleic acid metabolism gene expression. resulted specific deficiency levels apicoplast-encoded RNA not DNA. These reveal function maintenance suggest repurposed conserved scaffold heme-degrading ancestral chloroplast fulfill critical adaptive organelle

Language: Английский

Citations

1
Malaria parasites require a divergent heme oxygenase for apicoplast gene expression and biogenesis DOI Creative Commons
Amanda Mixon Blackwell, Yasaman Jami‐Alahmadi, Armiyaw S. Nasamu

et al.

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2024, Volume and Issue: unknown

Published: May 31, 2024

Malaria parasites have evolved unusual metabolic adaptations that specialize them for growth within heme-rich human erythrocytes. During blood-stage infection,

Language: Английский

Citations

1
Structural Insights into Mechanisms Underlying Mitochondrial and Bacterial Cytochrome c Synthases DOI Creative Commons

Pema L. Childs,

Ethan P. Lowder, Deanna L. Mendez

et al.

Biomolecules, Journal Year: 2024, Volume and Issue: 14(12), P. 1483 - 1483

Published: Nov. 21, 2024

Mitochondrial holocytochrome c synthase (HCCS) is an essential protein in assembling cytochrome (cyt c) of the electron transport system. HCCS binds heme and covalently attaches two vinyls to cysteine thiols cyt CXXCH motif. Human recognizes both c1 complex III (cytochrome bc1). mutated some human diseases it has been investigated recombinantly by mutational, biochemical, reconstitution studies past decade. Here, we employ structural prediction programs (e.g., AlphaFold 3) on its substrates, c. The results, when combined with spectroscopic functional analyses variants, provide insights into basis for binding, apocyt covalent attachment, release holocyt product. Results from vitro purified using peptides as acceptors are consistent modeling substrate binding. Reconstitution provides approach studying assembly, which refractile recombinant vivo (unlike c). We propose a product based cryoEM structures bacterial (CcsBA) active site. analyze kinetoplastid mitochondrial (KCCS), hypothesize molecular evolutionary path endosymbiosis current HCCS.

Language: Английский

Citations

0