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Oligomerization conditions for Frataxin

Wiemann, Mathias LU (2017) KEMP42 20162
Department of Chemistry
Abstract
Friedriech's ataxia is a serious neurological condition that is caused by a deficiency in the expression of the protein frataxin. This deficiency is caused by an extension of GAA repeats in the first intron of the frataxin-coding gene. The disease can have an onset as early as five years and by the time the patient has reached 20 years they often require a wheelchair and help to be able to have a functional life.
The exact role of frataxin in humans is currently not fully understood but it has been suggested that it plays part in several iron pathways in the mitochondria, including iron-sulfur(Fe-S) cluster synthesis. Frataxin can oligomerize in the presence of iron and this study is focused on better understanding of the mechanisms of... (More)
Friedriech's ataxia is a serious neurological condition that is caused by a deficiency in the expression of the protein frataxin. This deficiency is caused by an extension of GAA repeats in the first intron of the frataxin-coding gene. The disease can have an onset as early as five years and by the time the patient has reached 20 years they often require a wheelchair and help to be able to have a functional life.
The exact role of frataxin in humans is currently not fully understood but it has been suggested that it plays part in several iron pathways in the mitochondria, including iron-sulfur(Fe-S) cluster synthesis. Frataxin can oligomerize in the presence of iron and this study is focused on better understanding of the mechanisms of this process. The main focus of the study has been CyaY, a bacterial orthologue to human frataxin, that has a fold similar to that of its human counterpart.
The main method of investigation was dynamic light scattering (DLS). The oligomerization process was studied over time to see how oligomerization proceeded dependant on iron concentration. The effects of hydrogen peroxide, and indirectly the availability of Fe3+, on the size of the oligomers was investigated. Experiments were also performed to study the potential role of the protonation state of the protein in oligomerization by carrying out oligomerization experiments at pH 4.8. The effect of formation of Fe3+ after incubation with Fe2+ under anaerobic conditions was also followed. Finally, initial experiments to try to gain a better understanding of the effects of iron chelators and their interaction with frataxin were carried out.
In the study we show there is a difference in oligomerization behaviour depending on the iron-to-protein ratio, possibly due to filling the available iron-binding sites per monomer. Furthermore we show that the initial availability of Fe3+ have an effect on the size of the particles formed. Finally the study shows that oligomerization at pH 4.8 is severely repressed, although the reason for this repression is currently not clear since this could be due several different factors. (Less)
Popular Abstract (Swedish)
Järn är essentiellt för livet som vi känner det idag. Det är en del i flera av de huvudsakliga energisystemen som finns i de flesta levande organismer. Men järn som är fritt i en cell kan orsaka enorma skador genom att det deltar i en process som bildar så kallade syreradikaler. Det finns därför en mängd olika proteiner som på olika sätt binder och reglerar järn.
Fel med dessa proteiner kan leda till allvarliga sjukdomar. En av dessa sjukdomar är Friedreich's ataxi där de första symptomen kan göra sig kända så tidigt som vid fem års ålder. Sjukdomen utvecklas därefter och tjugo år gammal kan den drabbade vara behov av rullstol och assistans för att kunna klara sig.
Sjukdomen beror på att ett järnbindande protein kallat frataxin inte... (More)
Järn är essentiellt för livet som vi känner det idag. Det är en del i flera av de huvudsakliga energisystemen som finns i de flesta levande organismer. Men järn som är fritt i en cell kan orsaka enorma skador genom att det deltar i en process som bildar så kallade syreradikaler. Det finns därför en mängd olika proteiner som på olika sätt binder och reglerar järn.
Fel med dessa proteiner kan leda till allvarliga sjukdomar. En av dessa sjukdomar är Friedreich's ataxi där de första symptomen kan göra sig kända så tidigt som vid fem års ålder. Sjukdomen utvecklas därefter och tjugo år gammal kan den drabbade vara behov av rullstol och assistans för att kunna klara sig.
Sjukdomen beror på att ett järnbindande protein kallat frataxin inte uttrycks i tillräckligt stora mängder. Proteinets exakta funktion är inte helt utrett i nuläget men det verkar vara involverat i ett flertal olika processer där järn används som byggstenar för att skapa viktiga molekyler för kroppens funktioner.
Frataxin har förmågan att gå ihop och bilda större protein-sammanslutningar i närvaro av järn. Dessa sammanslutningar kan potentiellt vara viktiga för att förstå proteinets funktion i kroppen. Detta arbete har därför fokuserat på förutsättningarna för att bilda dessa proteinsammanslutningar för att öka förståelsen om frataxin och potentiellt leda till nya insikter hur man kan behandla Friedreich´s ataxia. (Less)
Please use this url to cite or link to this publication:
author
Wiemann, Mathias LU
supervisor
organization
course
KEMP42 20162
year
type
L3 - Miscellaneous, Projetcs etc.
subject
keywords
Frataxin, oligomerization, iron, protein science, proteinvetenskap
language
English
id
8928233
date added to LUP
2017-12-18 09:01:19
date last changed
2017-12-18 09:01:19
@misc{8928233,
  abstract     = {Friedriech's ataxia is a serious neurological condition that is caused by a deficiency in the expression of the protein frataxin. This deficiency is caused by an extension of GAA repeats in the first intron of the frataxin-coding gene. The disease can have an onset as early as five years and by the time the patient has reached 20 years they often require a wheelchair and help to be able to have a functional life.
The exact role of frataxin in humans is currently not fully understood but it has been suggested that it plays part in several iron pathways in the mitochondria, including iron-sulfur(Fe-S) cluster synthesis. Frataxin can oligomerize in the presence of iron and this study is focused on better understanding of the mechanisms of this process. The main focus of the study has been CyaY, a bacterial orthologue to human frataxin, that has a fold similar to that of its human counterpart. 
The main method of investigation was dynamic light scattering (DLS). The oligomerization process was studied over time to see how oligomerization proceeded dependant on iron concentration. The effects of hydrogen peroxide, and indirectly the availability of Fe3+, on the size of the oligomers was investigated. Experiments were also performed to study the potential role of the protonation state of the protein in oligomerization by carrying out oligomerization experiments at pH 4.8. The effect of formation of Fe3+ after incubation with Fe2+ under anaerobic conditions was also followed. Finally, initial experiments to try to gain a better understanding of the effects of iron chelators and their interaction with frataxin were carried out.
In the study we show there is a difference in oligomerization behaviour depending on the iron-to-protein ratio, possibly due to filling the available iron-binding sites per monomer. Furthermore we show that the initial availability of Fe3+ have an effect on the size of the particles formed. Finally the study shows that oligomerization at pH 4.8 is severely repressed, although the reason for this repression is currently not clear since this could be due several different factors.},
  author       = {Wiemann, Mathias},
  keyword      = {Frataxin,oligomerization,iron,protein science,proteinvetenskap},
  language     = {eng},
  note         = {Student Paper},
  title        = {Oligomerization conditions for Frataxin},
  year         = {2017},
}