TY - JOUR
T1 - Oligomerization propensity and flexibility of yeast frataxin studied by X-ray crystallography and small-angle X-ray scattering
AU - Söderberg, Christopher A.G.
AU - Shkumatov, Alexander V.
AU - Rajan, Sreekanth
AU - Gakh, Oleksandr
AU - Svergun, Dmitri I.
AU - Isaya, Grazia
AU - Al-Karadaghi, Salam
N1 - Funding Information:
This project was supported by the Swedish Research Council (Vetenskapsrådet) , a MAX IV/ESS grant from the Natural Science Faculty of Lund University , the Crafoord Foundation , and the Carl Trygger Foundation to S.A.-K. and by grant AG15709 from the National Institute on Aging, National Institutes of Health , to G.I. A.S. and D.S. would like to further acknowledge Bundesministerium für Bildung und Forschung Research Grant SYNC-LIFE (contract number 05K10YEA) and the EU FP7 e-Infrastructure grant WeNMR (contract number 261572). We also thank the European Molecular Biology Laboratory (Hamburg) and Lund University for synchrotron beam time allocation at DESY (Hamburg, Germany) and Max-Lab, respectively. Clement Blanchet and Tomás Plivelic are acknowledged for technical support at beam line X33 (DESY) and I711 (MAX-Lab), respectively.
PY - 2011/12/16
Y1 - 2011/12/16
N2 - Frataxin is a mitochondrial protein with a central role in iron homeostasis. Defects in frataxin function lead to Friedreich's ataxia, a progressive neurodegenerative disease with childhood onset. The function of frataxin has been shown to be closely associated with its ability to form oligomeric species; however, the factors controlling oligomerization and the types of oligomers present in solution are a matter of debate. Using small-angle X-ray scattering, we found that Co2+, glycerol, and a single amino acid substitution at the N-terminus, Y73A, facilitate oligomerization of yeast frataxin, resulting in a dynamic equilibrium between monomers, dimers, trimers, hexamers, and higher-order oligomers. Using X-ray crystallography, we found that Co2+ binds inside the channel at the 3-fold axis of the trimer, which suggests that the metal has an oligomer-stabilizing role. The results reveal the types of oligomers present in solution and support our earlier suggestions that the trimer is the main building block of yeast frataxin oligomers. They also indicate that different mechanisms may control oligomer stability and oligomerization in vivo.
AB - Frataxin is a mitochondrial protein with a central role in iron homeostasis. Defects in frataxin function lead to Friedreich's ataxia, a progressive neurodegenerative disease with childhood onset. The function of frataxin has been shown to be closely associated with its ability to form oligomeric species; however, the factors controlling oligomerization and the types of oligomers present in solution are a matter of debate. Using small-angle X-ray scattering, we found that Co2+, glycerol, and a single amino acid substitution at the N-terminus, Y73A, facilitate oligomerization of yeast frataxin, resulting in a dynamic equilibrium between monomers, dimers, trimers, hexamers, and higher-order oligomers. Using X-ray crystallography, we found that Co2+ binds inside the channel at the 3-fold axis of the trimer, which suggests that the metal has an oligomer-stabilizing role. The results reveal the types of oligomers present in solution and support our earlier suggestions that the trimer is the main building block of yeast frataxin oligomers. They also indicate that different mechanisms may control oligomer stability and oligomerization in vivo.
KW - Friedreich's ataxia
KW - metal chaperone
KW - neurodegenerative diseases
KW - protein flexibility
KW - protein oligomerization
UR - http://www.scopus.com/inward/record.url?scp=82555187015&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=82555187015&partnerID=8YFLogxK
U2 - 10.1016/j.jmb.2011.10.034
DO - 10.1016/j.jmb.2011.10.034
M3 - Article
C2 - 22051511
AN - SCOPUS:82555187015
SN - 0022-2836
VL - 414
SP - 783
EP - 797
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
IS - 5
ER -