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Your search keyword '"Park, Jaehyun"' showing total 730 results
Start Over Author "Park, Jaehyun" Publication Type Academic Journals
730 results on '"Park, Jaehyun"'

3. Optical control of ultrafast structural dynamics in a fluorescent protein.

Author

Hutchison, Christopher, Baxter, James, Fitzpatrick, Ann, Dorlhiac, Gabriel, Fadini, Alisia, Perrett, Samuel, Maghlaoui, Karim, Lefèvre, Salomé, Cordon-Preciado, Violeta, Ferreira, Josie, Chukhutsina, Volha, Garratt, Douglas, Barnard, Jonathan, Galinis, Gediminas, Glencross, Flo, Morgan, Rhodri, Stockton, Sian, Taylor, Ben, Yuan, Letong, Romei, Matthew, Lin, Chi-Yun, Marangos, Jon, Schmidt, Marius, Chatrchyan, Viktoria, Buckup, Tiago, Morozov, Dmitry, Park, Jaehyun, Park, Sehan, Eom, Intae, Kim, Minseok, Jang, Dogeun, Choi, Hyeongi, Hyun, HyoJung, Park, Gisu, Nango, Eriko, Tanaka, Rie, Owada, Shigeki, Tono, Kensuke, DePonte, Daniel, Carbajo, Sergio, Seaberg, Matt, Aquila, Andrew, Boutet, Sebastien, Barty, Anton, Iwata, So, Boxer, Steven, Groenhof, Gerrit, and van Thor, Jasper

Subjects
Motion, Vibration, Rhodopsin, Hydrogen Bonding
Abstract

The photoisomerization reaction of a fluorescent protein chromophore occurs on the ultrafast timescale. The structural dynamics that result from femtosecond optical excitation have contributions from vibrational and electronic processes and from reaction dynamics that involve the crossing through a conical intersection. The creation and progression of the ultrafast structural dynamics strongly depends on optical and molecular parameters. When using X-ray crystallography as a probe of ultrafast dynamics, the origin of the observed nuclear motions is not known. Now, high-resolution pump-probe X-ray crystallography reveals complex sub-ångström, ultrafast motions and hydrogen-bonding rearrangements in the active site of a fluorescent protein. However, we demonstrate that the measured motions are not part of the photoisomerization reaction but instead arise from impulsively driven coherent vibrational processes in the electronic ground state. A coherent-control experiment using a two-colour and two-pulse optical excitation strongly amplifies the X-ray crystallographic difference density, while it fully depletes the photoisomerization process. A coherent control mechanism was tested and confirmed the wave packets assignment.

Published
2023

11. Regulation of BRCA1 stability through the tandem UBX domains of isoleucyl-tRNA synthetase 1

Author

Chung, Scisung, Kang, Mi-Sun, Alimbetov, Dauren S, Mun, Gil-Im, Yunn, Na-Oh, Kim, Yunjin, Kim, Byung-Gyu, Wie, Minwoo, Lee, Eun A, Ra, Jae Sun, Oh, Jung-Min, Lee, Donghyun, Lee, Keondo, Kim, Jihan, Han, Seung Hyun, Kim, Kyong-Tai, Chung, Wan Kyun, Nam, Ki Hyun, Park, Jaehyun, Lee, ByungHoon, Kim, Sunghoon, Zhao, Weixing, Ryu, Sung Ho, Lee, Yun-Sil, Myung, Kyungjae, and Cho, Yunje

Subjects
Biochemistry and Cell Biology, Biological Sciences, 1.1 Normal biological development and functioning, Underpinning research, Isoleucine-tRNA Ligase, Amino Acyl-tRNA Synthetases, Glutamate-tRNA Ligase, RNA, Transfer
Abstract

Aminoacyl-tRNA synthetases (ARSs) have evolved to acquire various additional domains. These domains allow ARSs to communicate with other cellular proteins in order to promote non-translational functions. Vertebrate cytoplasmic isoleucyl-tRNA synthetases (IARS1s) have an uncharacterized unique domain, UNE-I. Here, we present the crystal structure of the chicken IARS1 UNE-I complexed with glutamyl-tRNA synthetase 1 (EARS1). UNE-I consists of tandem ubiquitin regulatory X (UBX) domains that interact with a distinct hairpin loop on EARS1 and protect its neighboring proteins in the multi-synthetase complex from degradation. Phosphomimetic mutation of the two serine residues in the hairpin loop releases IARS1 from the complex. IARS1 interacts with BRCA1 in the nucleus, regulates its stability by inhibiting ubiquitylation via the UBX domains, and controls DNA repair function.

Published
2022

18. e-Learning Readiness and Perceived Learning Workload among Students in an Indonesian University

Author

Widyanti, Ari, Hasudungan, Syalom, and Park, Jaehyun

Abstract

e-Learning has been widely used in educational settings especially in developing countries like Indonesia. The purpose of this study was to investigate e-learning readiness among Indonesian university students and to compare students' perceptions of their workload (including mental demand, physical demand, temporal demand, performance, effort, frustration, and sleepiness) in e-learning and classical learning settings. A survey was conducted with students in an Indonesian university. The results show that students have a high level of e-learning readiness. Mental workload is significantly higher in e-learning than in face-to-face learning. No significant difference in sleepiness was found between e-learning and face-to-face learning. The correlation between e-learning readiness and the mental workload was not significant. Implications of the results are discussed.

Published
2020

40. Room temperature XFEL crystallography reveals asymmetry in the vicinity of the two phylloquinones in photosystem I

Author

Keable, Stephen M, Kölsch, Adrian, Simon, Philipp S, Dasgupta, Medhanjali, Chatterjee, Ruchira, Subramanian, Senthil Kumar, Hussein, Rana, Ibrahim, Mohamed, Kim, In-Sik, Bogacz, Isabel, Makita, Hiroki, Pham, Cindy C, Fuller, Franklin D, Gul, Sheraz, Paley, Daniel, Lassalle, Louise, Sutherlin, Kyle D, Bhowmick, Asmit, Moriarty, Nigel W, Young, Iris D, Blaschke, Johannes P, de Lichtenberg, Casper, Chernev, Petko, Cheah, Mun Hon, Park, Sehan, Park, Gisu, Kim, Jangwoo, Lee, Sang Jae, Park, Jaehyun, Tono, Kensuke, Owada, Shigeki, Hunter, Mark S, Batyuk, Alexander, Oggenfuss, Roland, Sander, Mathias, Zerdane, Serhane, Ozerov, Dmitry, Nass, Karol, Lemke, Henrik, Mankowsky, Roman, Brewster, Aaron S, Messinger, Johannes, Sauter, Nicholas K, Yachandra, Vittal K, Yano, Junko, Zouni, Athina, and Kern, Jan

Subjects
Physical Sciences, Chemical Sciences, Physical Chemistry, Crystallography, X-Ray, Photosynthesis, Photosystem I Protein Complex, Protein Structure, Tertiary, Temperature, Thermosynechococcus, Vitamin K 1
Abstract

Photosystem I (PS I) has a symmetric structure with two highly similar branches of pigments at the center that are involved in electron transfer, but shows very different efficiency along the two branches. We have determined the structure of cyanobacterial PS I at room temperature (RT) using femtosecond X-ray pulses from an X-ray free electron laser (XFEL) that shows a clear expansion of the entire protein complex in the direction of the membrane plane, when compared to previous cryogenic structures. This trend was observed by complementary datasets taken at multiple XFEL beamlines. In the RT structure of PS I, we also observe conformational differences between the two branches in the reaction center around the secondary electron acceptors A1A and A1B. The π-stacked Phe residues are rotated with a more parallel orientation in the A-branch and an almost perpendicular confirmation in the B-branch, and the symmetry breaking PsaB-Trp673 is tilted and further away from A1A. These changes increase the asymmetry between the branches and may provide insights into the preferential directionality of electron transfer.

Published
2021

41. High-Resolution XFEL Structure of the Soluble Methane Monooxygenase Hydroxylase Complex with its Regulatory Component at Ambient Temperature in Two Oxidation States

Author

Srinivas, Vivek, Banerjee, Rahul, Lebrette, Hugo, Jones, Jason C, Aurelius, Oskar, Kim, In-Sik, Pham, Cindy C, Gul, Sheraz, Sutherlin, Kyle D, Bhowmick, Asmit, John, Juliane, Bozkurt, Esra, Fransson, Thomas, Aller, Pierre, Butryn, Agata, Bogacz, Isabel, Simon, Philipp, Keable, Stephen, Britz, Alexander, Tono, Kensuke, Kim, Kyung Sook, Park, Sang-Youn, Lee, Sang Jae, Park, Jaehyun, Alonso-Mori, Roberto, Fuller, Franklin D, Batyuk, Alexander, Brewster, Aaron S, Bergmann, Uwe, Sauter, Nicholas K, Orville, Allen M, Yachandra, Vittal K, Yano, Junko, Lipscomb, John D, Kern, Jan, and Högbom, Martin

Subjects
Inorganic Chemistry, Chemical Sciences, Methylosinus trichosporium, Models, Molecular, Oxidation-Reduction, Oxygenases, Solubility, Temperature, X-Rays, General Chemistry, Chemical sciences, Engineering
Abstract

Soluble methane monooxygenase (sMMO) is a multicomponent metalloenzyme that catalyzes the conversion of methane to methanol at ambient temperature using a nonheme, oxygen-bridged dinuclear iron cluster in the active site. Structural changes in the hydroxylase component (sMMOH) containing the diiron cluster caused by complex formation with a regulatory component (MMOB) and by iron reduction are important for the regulation of O2 activation and substrate hydroxylation. Structural studies of metalloenzymes using traditional synchrotron-based X-ray crystallography are often complicated by partial X-ray-induced photoreduction of the metal center, thereby obviating determination of the structure of the enzyme in pure oxidation states. Here, microcrystals of the sMMOH:MMOB complex from Methylosinus trichosporium OB3b were serially exposed to X-ray free electron laser (XFEL) pulses, where the ≤35 fs duration of exposure of an individual crystal yields diffraction data before photoreduction-induced structural changes can manifest. Merging diffraction patterns obtained from thousands of crystals generates radiation damage-free, 1.95 Å resolution crystal structures for the fully oxidized and fully reduced states of the sMMOH:MMOB complex for the first time. The results provide new insight into the manner by which the diiron cluster and the active site environment are reorganized by the regulatory protein component in order to enhance the steps of oxygen activation and methane oxidation. This study also emphasizes the value of XFEL and serial femtosecond crystallography (SFX) methods for investigating the structures of metalloenzymes with radiation sensitive metal active sites.

Published
2020

48. Atomically thin three-dimensional membranes of van der Waals semiconductors by wafer-scale growth.

Author

Jin, Gangtae, Lee, Chang-Soo, Liao, Xing, Kim, Juho, Wang, Zhen, Okello, Odongo, Park, Bumsu, Park, Jaehyun, Han, Cheolhee, Heo, Hoseok, Kim, Jonghwan, Oh, Sang, Choi, Si-Young, Park, Hongkun, and Jo, Moon-Ho

Abstract

We report wafer-scale growth of atomically thin, three-dimensional (3D) van der Waals (vdW) semiconductor membranes. By controlling the growth kinetics in the near-equilibrium limit during metal-organic chemical vapor depositions of MoS2 and WS2 monolayer (ML) crystals, we have achieved conformal ML coverage on diverse 3D texture substrates, such as periodic arrays of nanoscale needles and trenches on quartz and SiO2/Si substrates. The ML semiconductor properties, such as channel resistivity and photoluminescence, are verified to be seamlessly uniform over the 3D textures and are scalable to wafer scale. In addition, we demonstrated that these 3D films can be easily delaminated from the growth substrates to form suspended 3D semiconductor membranes. Our work suggests that vdW ML semiconductor films can be useful platforms for patchable membrane electronics with atomic precision, yet large areas, on arbitrary substrates.

Published
2019

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