scholarly journals Proteins of the Glycine Decarboxylase Complex in the Hydrogenosome of Trichomonas vaginalis

2006 ◽  
Vol 5 (12) ◽  
pp. 2062-2071 ◽  
Author(s):  
Mandira Mukherjee ◽  
Mark T. Brown ◽  
Andrew G. McArthur ◽  
Patricia J. Johnson
Keyword(s):  
Trichomonas Vaginalis ◽  
Phylogenetic Analyses ◽  
Unicellular Eukaryote ◽  
Cluster Assembly ◽  
Glycine Decarboxylase ◽  
Iron Sulfur Cluster ◽  
Transfer Event ◽  
L Protein ◽  
Glycine Decarboxylase Complex ◽  
L Proteins

ABSTRACT Trichomonas vaginalis is a unicellular eukaryote that lacks mitochondria and contains a specialized organelle, the hydrogenosome, involved in carbohydrate metabolism and iron-sulfur cluster assembly. We report the identification of two glycine cleavage H proteins and a dihydrolipoamide dehydrogenase (L protein) of the glycine decarboxylase complex in T. vaginalis with predicted N-terminal hydrogenosomal presequences. Immunofluorescence analyses reveal that both H and L proteins are localized in hydrogenosomes, providing the first evidence for amino acid metabolism in this organelle. All three proteins were expressed in Escherichia coli and purified to homogeneity. The experimental Km of L protein for the two H proteins were 2.6 μM and 3.7 μM, consistent with both H proteins serving as substrates of L protein. Analyses using purified hydrogenosomes showed that endogenous H proteins exist as monomers and endogenous L protein as a homodimer in their native states. Phylogenetic analyses of L proteins revealed that the T. vaginalis homologue shares a common ancestry with dihydrolipoamide dehydrogenases from the firmicute bacteria, indicating its acquisition via a horizontal gene transfer event independent of the origins of mitochondria and hydrogenosomes.

scholarly journals Characterization and Reconstitution of Human Lipoyl Synthase (LIAS) Supports ISCA2 and ISCU as Primary Cluster Donors and an Ordered Mechanism of Cluster Assembly

2021 ◽  
Vol 22 (4) ◽  
pp. 1598
Author(s):  
Amber L. Hendricks ◽  
Christine Wachnowsky ◽  
Brian Fries ◽  
Insiya Fidai ◽  
James A. Cowan
Keyword(s):  
Cluster Assembly ◽  
Paramagnetic Resonance ◽  
Iron Sulfur Cluster ◽  
Sulfur Transfer ◽  
Disease States ◽  
Isolation And Characterization ◽  
Iron Sulfur ◽  
Natural Iron ◽  
Lipoyl Synthase

Lipoyl synthase (LIAS) is an iron–sulfur cluster protein and a member of the radical S-adenosylmethionine (SAM) superfamily that catalyzes the final step of lipoic acid biosynthesis. The enzyme contains two [4Fe–4S] centers (reducing and auxiliary clusters) that promote radical formation and sulfur transfer, respectively. Most information concerning LIAS and its mechanism has been determined from prokaryotic enzymes. Herein, we detail the expression, isolation, and characterization of human LIAS, its reactivity, and evaluation of natural iron–sulfur (Fe–S) cluster reconstitution mechanisms. Cluster donation by a number of possible cluster donor proteins and heterodimeric complexes has been evaluated. [2Fe–2S]-cluster-bound forms of human ISCU and ISCA2 were found capable of reconstituting human LIAS, such that complete product turnover was enabled for LIAS, as monitored via a liquid chromatography–mass spectrometry (LC–MS) assay. Electron paramagnetic resonance (EPR) studies of native LIAS and substituted derivatives that lacked the ability to bind one or the other of LIAS’s two [4Fe–4S] clusters revealed a likely order of cluster addition, with the auxiliary cluster preceding the reducing [4Fe–4S] center. These results detail the trafficking of Fe–S clusters in human cells and highlight differences with respect to bacterial LIAS analogs. Likely in vivo Fe–S cluster donors to LIAS are identified, with possible connections to human disease states, and a mechanistic ordering of [4Fe–4S] cluster reconstitution is evident.

scholarly journals MRE11 Is Crucial for Malaria Parasite Transmission and Its Absence Affects Expression of Interconnected Networks of Key Genes Essential for Life

Cells ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2590
Author(s):  
David S. Guttery ◽  
Abhinay Ramaprasad ◽  
David J. P. Ferguson ◽  
Mohammad Zeeshan ◽  
Rajan Pandey ◽  
...  
Keyword(s):  
Genome Stability ◽  
Malaria Parasite ◽  
Mosquito Vector ◽  
Parasite Transmission ◽  
Biological Processes ◽  
Cluster Assembly ◽  
Iron Sulfur Cluster ◽  
Iron Sulfur ◽  
Parasite Plasmodium ◽  
Damage Response

The meiotic recombination 11 protein (MRE11) plays a key role in DNA damage response and maintenance of genome stability. However, little is known about its function during development of the malaria parasite Plasmodium. Here, we present a functional, ultrastructural and transcriptomic analysis of Plasmodium parasites lacking MRE11 during its life cycle in both mammalian and mosquito vector hosts. Genetic disruption of Plasmodium berghei mre11 (PbMRE11) results in significant retardation of oocyst development in the mosquito midgut associated with cytoplasmic and nuclear degeneration, along with concomitant ablation of sporogony and subsequent parasite transmission. Further, absence of PbMRE11 results in significant transcriptional downregulation of genes involved in key interconnected biological processes that are fundamental to all eukaryotic life including ribonucleoprotein biogenesis, spliceosome function and iron–sulfur cluster assembly. Overall, our study provides a comprehensive functional analysis of MRE11′s role in Plasmodium development during the mosquito stages and offers a potential target for therapeutic intervention during malaria parasite transmission.

scholarly journals Multiple Sense and Antisense Promoters Contribute to the Regulated Expression of the isc-suf Operon for Iron-Sulfur Cluster Assembly in Rhodobacter

2019 ◽  
Vol 7 (12) ◽  
pp. 671 ◽  
Author(s):  
Xin Nie ◽  
Bernhard Remes ◽  
Gabriele Klug
Keyword(s):  
Rhodobacter Sphaeroides ◽  
Photosynthetic Electron Transport ◽  
Regulatory Proteins ◽  
Cluster Assembly ◽  
Iron Sulfur Cluster ◽  
Iron Sulfur Clusters ◽  
Sulfur Cluster ◽  
Iron Sulfur ◽  
Photosynthetic Complexes ◽  
The One

A multitude of biological functions relies on iron-sulfur clusters. The formation of photosynthetic complexes goes along with an additional demand for iron-sulfur clusters for bacteriochlorophyll synthesis and photosynthetic electron transport. However, photooxidative stress leads to the destruction of iron-sulfur clusters, and the released iron promotes the formation of further reactive oxygen species. A balanced regulation of iron-sulfur cluster synthesis is required to guarantee the supply of this cofactor, on the one hand, but also to limit stress, on the other hand. The phototrophic alpha-proteobacterium Rhodobacter sphaeroides harbors a large operon for iron-sulfur cluster assembly comprising the iscRS and suf genes. IscR (iron-sulfur cluster regulator) is an iron-dependent regulator of isc-suf genes and other genes with a role in iron metabolism. We applied reporter gene fusions to identify promoters of the isc-suf operon and studied their activity alone or in combination under different conditions. Gel-retardation assays showed the binding of regulatory proteins to individual promoters. Our results demonstrated that several promoters in a sense and antisense direction influenced isc-suf expression and the binding of the IscR, Irr, and OxyR regulatory proteins to individual promoters. These findings demonstrated a complex regulatory network of several promoters and regulatory proteins that helped to adjust iron-sulfur cluster assembly to changing conditions in Rhodobacter sphaeroides.

scholarly journals Spliceosomal snRNAs in the unicellular eukaryote Trichomonas vaginalis are structurally conserved but lack a 5'-cap structure

RNA ◽  
2008 ◽  
Vol 14 (8) ◽  
pp. 1617-1631 ◽  
Author(s):  
A. Simoes-Barbosa ◽  
D. Meloni ◽  
J. A. Wohlschlegel ◽  
M. M. Konarska ◽  
P. J. Johnson
Keyword(s):  
Trichomonas Vaginalis ◽  
Unicellular Eukaryote

scholarly journals Regulation of the HscA ATPase Reaction Cycle by the Co-chaperone HscB and the Iron-Sulfur Cluster Assembly Protein IscU

2004 ◽  
Vol 279 (52) ◽  
pp. 53924-53931 ◽  
Author(s):  
Jonathan J. Silberg ◽  
Tim L. Tapley ◽  
Kevin G. Hoff ◽  
Larry E. Vickery
Keyword(s):  
Cluster Assembly ◽  
Iron Sulfur Cluster ◽  
Reaction Cycle ◽  
Sulfur Cluster ◽  
Iron Sulfur ◽  
Atpase Reaction

scholarly journals Presence of a Member of the Mitochondrial Carrier Family in Hydrogenosomes: Conservation of Membrane-Targeting Pathways between Hydrogenosomes and Mitochondria

2000 ◽  
Vol 20 (7) ◽  
pp. 2488-2497 ◽  
Author(s):  
Sabrina D. Dyall ◽  
Carla M. Koehler ◽  
Maria G. Delgadillo-Correa ◽  
Peter J. Bradley ◽  
Evelyn Plümper ◽  
...  
Keyword(s):  
Trichomonas Vaginalis ◽  
Protein Targeting ◽  
Phylogenetic Analyses ◽  
Eukaryotic Cell ◽  
Membrane Targeting ◽  
Carrier Proteins ◽  
Mitochondrial Carrier ◽  
Mitochondrial Carrier Family ◽  
Targeting Signal ◽  
Mitochondrial Carrier Proteins

ABSTRACT A number of microaerophilic eukaryotes lack mitochondria but possess another organelle involved in energy metabolism, the hydrogenosome. Limited phylogenetic analyses of nuclear genes support a common origin for these two organelles. We have identified a protein of the mitochondrial carrier family in the hydrogenosome ofTrichomonas vaginalis and have shown that this protein, Hmp31, is phylogenetically related to the mitochondrial ADP-ATP carrier (AAC). We demonstrate that the hydrogenosomal AAC can be targeted to the inner membrane of mitochondria isolated from Saccharomyces cerevisiae through the Tim9-Tim10 import pathway used for the assembly of mitochondrial carrier proteins. Conversely, yeast mitochondrial AAC can be targeted into the membranes of hydrogenosomes. The hydrogenosomal AAC contains a cleavable, N-terminal presequence; however, this sequence is not necessary for targeting the protein to the organelle. These data indicate that the membrane-targeting signal(s) for hydrogenosomal AAC is internal, similar to that found for mitochondrial carrier proteins. Our findings indicate that the membrane carriers and membrane protein-targeting machinery of hydrogenosomes and mitochondria have a common evolutionary origin. Together, they provide strong evidence that a single endosymbiont evolved into a progenitor organelle in early eukaryotic cells that ultimately give rise to these two distinct organelles and support the hydrogen hypothesis for the origin of the eukaryotic cell.

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