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Characterization of the protein import into Giardia Intestinalis mitosomes
Pyrihová, Eva ; Doležal, Pavel (advisor) ; Tsaousis, Anastasios (referee) ; Stairs, Courtney (referee)
Mitochondrial endosymbiosis was a key event in the evolution of eukaryotes. Its proteome evolved into a unique combination of inherited bacterial components as well as novel eukaryotic inventions. Today, mitochondria show a huge variety across eukaryotic species - from aerobic mitochondria with cristae and complex protein apparatus for maintaining its own genome to hydrogen-producing hydrogenosomes and tiny anaerobic mitosomes without their own genome and with only a single metabolic pathway. Comparing the existing spectra of mitochondria is beneficial for studying their evolution. The only ubiquitous and unifying features are double membrane, ISC pathway for iron-sulfur cluster synthesis and the core of protein import pathway. Therefore, these features could be considered as truly ancestral and essential to mitochondria. Mitosomes of various parasitic protists have evolved independently from complex mitochondria, since they are present in completely unrelated species and yet their evolution led in a surprisingly similar composition of protein import pathway. These retained components are thus believed to be functionally essential and for some reason hard to be replaced by alternate proteins. Mitosomal import pathways were considered very minimalistic for a long time. Nevertheless, the latest...
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Iron-Sulfur cluster assembly in Monocercomonoides exilis
Vacek, Vojtěch ; Hampl, Vladimír (advisor) ; Balk, Janneke (referee) ; Tsaousis, Anastasios (referee)
In the search for the mitochondrion of oxymonads, DNA of Monocercomonoides exilis - an oxymonad isolated from the gut of Chinchilla, was isolated and its genome was sequenced. Sequencing resulted in a fairly complete genome which was extensively searched or genes for mitochondrion related proteins, but no reliable candidate for such gene was identified. Even genes for the ISC pathway, which is responsible for Fe-S cluster assembly and considered to be the only essential function of reduced mitochondrion-like organelles (MROs), were absent. Instead, we were able to detect the presence of a SUF pathway which functionally replaced the ISC pathway. Closer examination of the SUF pathway based on heterologous localisation revealed that this pathway localised in the cytosol. In silico analysis showed that SUF genes are highly conserved at the level of secondary and tertiary structure and most catalytic residues and motifs are present in their sequences. The functionality of these proteins was further indirectly confirmed by complementation experiments in Escherichia coli where SUF proteins of M. exilis were able to restore at least partially Fe-S cluster assembly of strains deficient in the SUF and ISC pathways. We also proved by bacterial adenylate cyclase two-hybrid system that SufB and SufC can form...
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Iron-Sulfur cluster assembly in Monocercomonoides exilis
Vacek, Vojtěch ; Hampl, Vladimír (advisor) ; Balk, Janneke (referee) ; Tsaousis, Anastasios (referee)
In the search for the mitochondrion of oxymonads, DNA of Monocercomonoides exilis - an oxymonad isolated from the gut of Chinchilla, was isolated and its genome was sequenced. Sequencing resulted in a fairly complete genome which was extensively searched or genes for mitochondrion related proteins, but no reliable candidate for such gene was identified. Even genes for the ISC pathway, which is responsible for Fe-S cluster assembly and considered to be the only essential function of reduced mitochondrion-like organelles (MROs), were absent. Instead, we were able to detect the presence of a SUF pathway which functionally replaced the ISC pathway. Closer examination of the SUF pathway based on heterologous localisation revealed that this pathway localised in the cytosol. In silico analysis showed that SUF genes are highly conserved at the level of secondary and tertiary structure and most catalytic residues and motifs are present in their sequences. The functionality of these proteins was further indirectly confirmed by complementation experiments in Escherichia coli where SUF proteins of M. exilis were able to restore at least partially Fe-S cluster assembly of strains deficient in the SUF and ISC pathways. We also proved by bacterial adenylate cyclase two-hybrid system that SufB and SufC can form...
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Characterization of the protein import into Giardia Intestinalis mitosomes
Pyrihová, Eva ; Doležal, Pavel (advisor) ; Tsaousis, Anastasios (referee) ; Stairs, Courtney (referee)
Mitochondrial endosymbiosis was a key event in the evolution of eukaryotes. Its proteome evolved into a unique combination of inherited bacterial components as well as novel eukaryotic inventions. Today, mitochondria show a huge variety across eukaryotic species - from aerobic mitochondria with cristae and complex protein apparatus for maintaining its own genome to hydrogen-producing hydrogenosomes and tiny anaerobic mitosomes without their own genome and with only a single metabolic pathway. Comparing the existing spectra of mitochondria is beneficial for studying their evolution. The only ubiquitous and unifying features are double membrane, ISC pathway for iron-sulfur cluster synthesis and the core of protein import pathway. Therefore, these features could be considered as truly ancestral and essential to mitochondria. Mitosomes of various parasitic protists have evolved independently from complex mitochondria, since they are present in completely unrelated species and yet their evolution led in a surprisingly similar composition of protein import pathway. These retained components are thus believed to be functionally essential and for some reason hard to be replaced by alternate proteins. Mitosomal import pathways were considered very minimalistic for a long time. Nevertheless, the latest...
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