Hai-Young Kim

Publications (22) View all

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  Available from: Hai-Young Kim

  Article: Cold denaturation of a protein dimer monitored at atomic resolution.

  Mariusz Jaremko, Lukasz Jaremko, Hai-Young Kim, Min-Kyu Cho, Charles D Schwieters, Karin Giller, Stefan Becker, Markus Zweckstetter
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  ABSTRACT: Protein folding and unfolding are crucial for a range of biological phenomena and human diseases. Defining the structural properties of the involved transient species is therefore of prime interest. Using a combination of cold denaturation with NMR spectroscopy, we reveal detailed insight into the unfolding of the homodimeric repressor protein CylR2. Seven three-dimensional structures of CylR2 at temperatures from 25 °C to -16 °C reveal a progressive dissociation of the dimeric protein into a native-like monomeric intermediate followed by transition into a highly dynamic, partially folded state. The core of the partially folded state seems critical for biological function and misfolding.
  Nature Chemical Biology 02/2013; · 14.69 Impact Factor
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  Available from: Min-Kyu Cho

  Article: Cold-induced changes in the protein ubiquitin.

  Min-Kyu Cho, Shengqi Xiang, Hai-Young Kim, Stefan Becker, Markus Zweckstetter
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  ABSTRACT: Conformational changes are essential for protein-protein and protein-ligand recognition. Here we probed changes in the structure of the protein ubiquitin at low temperatures in supercooled water using NMR spectroscopy. We demonstrate that ubiquitin is well folded down to 263 K, although slight rearrangements in the hydrophobic core occur. However, amide proton chemical shifts show non-linear temperature dependence in supercooled solution and backbone hydrogen bonds become weaker in the region that is most prone to cold-denaturation. Our data suggest that the weakening of the hydrogen bonds in the β-sheet of ubiquitin might be one of the first events that occur during cold-denaturation of ubiquitin. Interestingly, the same region is strongly involved in ubiquitin-protein complexes suggesting that this part of ubiquitin more easily adjusts to conformational changes required for complex formation.
  PLoS ONE 01/2012; 7(6):e37270. · 4.09 Impact Factor
• Article: Conserved core of amyloid fibrils of wild type and A30P mutant α-synuclein.

  Min-Kyu Cho, Hai-Young Kim, Claudio O Fernandez, Stefan Becker, Markus Zweckstetter
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  ABSTRACT: The major component of neural inclusions that are the pathological hallmark of Parkinson's disease are amyloid fibrils of the protein α-synuclein (aS). Here we investigated if the disease-related mutation A30P not only modulates the kinetics of aS aggregation, but also alters the structure of amyloid fibrils. To this end we optimized the method of quenched hydrogen/deuterium exchange coupled to NMR spectroscopy and performed two-dimensional proton-detected high-resolution magic angle spinning experiments. The combined data indicate that the A30P mutation does not cause changes in the number, location and overall arrangement of β-strands in amyloid fibrils of aS. At the same time, several residues within the fibrillar core retain nano-second dynamics. We conclude that the increased pathogenicity related to the familial A30P mutation is unlikely to be caused by a mutation-induced change in the conformation of aS aggregates.
  Protein Science 02/2011; 20(2):387-95. · 2.80 Impact Factor
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  Available from: Min-Kyu Cho

  Article: Integrated analysis of the conformation of a protein-linked spin label by crystallography, EPR and NMR spectroscopy.

  Tim Gruene, Min-Kyu Cho, Irina Karyagina, Hai-Young Kim, Christian Grosse, Karin Giller, Markus Zweckstetter, Stefan Becker
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  ABSTRACT: Long-range structural information derived from paramagnetic relaxation enhancement observed in the presence of a paramagnetic nitroxide radical is highly useful for structural characterization of globular, modular and intrinsically disordered proteins, as well as protein-protein and protein-DNA complexes. Here we characterized the conformation of a spin-label attached to the homodimeric protein CylR2 using a combination of X-ray crystallography, electron paramagnetic resonance (EPR) and NMR spectroscopy. Close agreement was found between the conformation of the spin label observed in the crystal structure with interspin distances measured by EPR and signal broadening in NMR spectra, suggesting that the conformation seen in the crystal structure is also preferred in solution. In contrast, conformations of the spin label observed in crystal structures of T4 lysozyme are not in agreement with the paramagnetic relaxation enhancement observed for spin-labeled CylR2 in solution. Our data demonstrate that accurate positioning of the paramagnetic center is essential for high-resolution structure determination.
  Journal of Biomolecular NMR 02/2011; 49(2):111-9. · 3.61 Impact Factor
• Article: Phosphorylation at S87 is enhanced in synucleinopathies, inhibits alpha-synuclein oligomerization, and influences synuclein-membrane interactions.

  Katerina E Paleologou, Abid Oueslati, Gideon Shakked, Carla C Rospigliosi, Hai-Young Kim, Gonzalo R Lamberto, Claudio O Fernandez, Adrian Schmid, Fariba Chegini, Wei Ping Gai, Diego Chiappe, Marc Moniatte, Bernard L Schneider, Patrick Aebischer, David Eliezer, Markus Zweckstetter, Eliezer Masliah, Hilal A Lashuel
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  ABSTRACT: Increasing evidence suggests that phosphorylation may play an important role in the oligomerization, fibrillogenesis, Lewy body (LB) formation, and neurotoxicity of alpha-synuclein (alpha-syn) in Parkinson disease. Herein we demonstrate that alpha-syn is phosphorylated at S87 in vivo and within LBs. The levels of S87-P are increased in brains of transgenic (TG) models of synucleinopathies and human brains from Alzheimer disease (AD), LB disease (LBD), and multiple system atrophy (MSA) patients. Using antibodies against phosphorylated alpha-syn (S129-P and S87-P), a significant amount of immunoreactivity was detected in the membrane in the LBD, MSA, and AD cases but not in normal controls. In brain homogenates from diseased human brains and TG animals, the majority of S87-P alpha-syn was detected in the membrane fractions. A battery of biophysical methods were used to dissect the effect of S87 phosphorylation on the structure, aggregation, and membrane-binding properties of monomeric alpha-syn. These studies demonstrated that phosphorylation at S87 expands the structure of alpha-syn, increases its conformational flexibility, and blocks its fibrillization in vitro. Furthermore, phosphorylation at S87, but not S129, results in significant reduction of alpha-syn binding to membranes. Together, our findings provide novel mechanistic insight into the role of phosphorylation at S87 and S129 in the pathogenesis of synucleinopathies and potential roles of phosphorylation in alpha-syn normal biology.
  Journal of Neuroscience 03/2010; 30(9):3184-98. · 7.11 Impact Factor