1
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Bock LV, Igaev M, Grubmüller H. Single-particle Cryo-EM and molecular dynamics simulations: A perfect match. Curr Opin Struct Biol 2024; 86:102825. [PMID: 38723560 DOI: 10.1016/j.sbi.2024.102825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 04/08/2024] [Accepted: 04/09/2024] [Indexed: 05/19/2024]
Abstract
Knowledge of the structure and dynamics of biomolecules is key to understanding the mechanisms underlying their biological functions. Single-particle cryo-electron microscopy (cryo-EM) is a powerful structural biology technique to characterize complex biomolecular systems. Here, we review recent advances of how Molecular Dynamics (MD) simulations are being used to increase and enhance the information extracted from cryo-EM experiments. We will particularly focus on the physics underlying these experiments, how MD facilitates structure refinement, in particular for heterogeneous and non-isotropic resolution, and how thermodynamic and kinetic information can be extracted from cryo-EM data.
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Affiliation(s)
- Lars V Bock
- Theoretical and Computational Biophysics Department, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, Göttingen, 37077, Germany. https://twitter.com/Pogoscience
| | - Maxim Igaev
- Theoretical and Computational Biophysics Department, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, Göttingen, 37077, Germany. https://twitter.com/maxotubule
| | - Helmut Grubmüller
- Theoretical and Computational Biophysics Department, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, Göttingen, 37077, Germany.
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2
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Wakabayashi T, Oide M, Nakasako M. CryoEM-sampling of metastable conformations appearing in cofactor-ligand association and catalysis of glutamate dehydrogenase. Sci Rep 2024; 14:11165. [PMID: 38750092 PMCID: PMC11096400 DOI: 10.1038/s41598-024-61793-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 05/09/2024] [Indexed: 05/18/2024] Open
Abstract
Kinetic aspects of enzymatic reactions are described by equations based on the Michaelis-Menten theory for the initial stage. However, the kinetic parameters provide little information on the atomic mechanism of the reaction. In this study, we analyzed structures of glutamate dehydrogenase in the initial and steady stages of the reaction using cryoEM at near-atomic resolution. In the initial stage, four metastable conformations displayed different domain motions and cofactor/ligand association modes. The most striking finding was that the enzyme-cofactor-substrate complex, treated as a single state in the enzyme kinetic theory, comprised at least three different metastable conformations. In the steady stage, seven conformations, including derivatives from the four conformations in the initial stage, made the reaction pathway complicated. Based on the visualized conformations, we discussed stage-dependent pathways to illustrate the dynamics of the enzyme in action.
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Grants
- JPMJPR22E2 Japan Science and Technology Agency
- jp13480214 Japan Society for the Promotion of Science
- jp19204042 Japan Society for the Promotion of Science
- jp22244054 Japan Society for the Promotion of Science
- jp21H01050 Japan Society for the Promotion of Science
- jp26800227 Japan Society for the Promotion of Science
- 18J11653 Japan Society for the Promotion of Science
- jp15076210 Ministry of Education, Culture, Sports, Science and Technology of Japan
- jp20050030 Ministry of Education, Culture, Sports, Science and Technology of Japan
- jp22018027 Ministry of Education, Culture, Sports, Science and Technology of Japan
- jp23120525, jp25120725 Ministry of Education, Culture, Sports, Science and Technology of Japan
- jp15H01647 Ministry of Education, Culture, Sports, Science and Technology of Japan
- jp17H05891 Ministry of Education, Culture, Sports, Science and Technology of Japan
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Affiliation(s)
- Taiki Wakabayashi
- Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoko-Ku, Yokohama, Kanagawa, 223-8522, Japan
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-Cho, Sayo-Gun, Hyogo, 679-5148, Japan
| | - Mao Oide
- Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoko-Ku, Yokohama, Kanagawa, 223-8522, Japan
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-Cho, Sayo-Gun, Hyogo, 679-5148, Japan
- PRESTO, Japan Science and Technology Agency, Chiyoda-Ku, Tokyo, 102-0076, Japan
- Protein Research Institute, Osaka University, Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Masayoshi Nakasako
- Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoko-Ku, Yokohama, Kanagawa, 223-8522, Japan.
- RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-Cho, Sayo-Gun, Hyogo, 679-5148, Japan.
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3
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Yoshidome T. Four-dimensional imaging for cryo-electron microscopy experiments using molecular simulations and manifold learning. J Comput Chem 2024; 45:738-751. [PMID: 38112413 DOI: 10.1002/jcc.27290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 11/20/2023] [Accepted: 12/01/2023] [Indexed: 12/21/2023]
Abstract
Elucidating protein conformational changes is essential because conformational changes are closely related to the functions of proteins. Cryo-electron microscopy (cryo-EM) experiment can be used to reconstruct protein conformational changes via a method that involves using the experimental data (two-dimensional protein images). In this study, a reconstruction method, referred to as the "four-dimensional imaging," was proposed. In our four-dimensional imaging technique, the protein conformational change was obtained using the two-dimensional protein images (the three-dimensional electron density maps used in previously proposed techniques were not used). The protein conformation for each two-dimensional protein image was obtained using our original protocol with molecular dynamics simulations. Using a manifold-learning technique and two-dimensional protein images, the protein conformations were arranged according to the conformational change of the protein. By arranging the protein conformations according to the arrangement of the protein images, four-dimensional imaging is constructed. A simulation for a cryo-EM experiment demonstrated the validity of our four-dimensional imaging technique.
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Affiliation(s)
- Takashi Yoshidome
- Department of Applied Physics, Graduate School of Engineering, Tohoku University, Sendai, Japan
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4
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Feng Z, Alvarenga OE, Accardi A. Structural basis of closed groove scrambling by a TMEM16 protein. Nat Struct Mol Biol 2024:10.1038/s41594-024-01284-9. [PMID: 38684930 DOI: 10.1038/s41594-024-01284-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 03/21/2024] [Indexed: 05/02/2024]
Abstract
Activation of Ca2+-dependent TMEM16 scramblases induces phosphatidylserine externalization, a key step in multiple signaling processes. Current models suggest that the TMEM16s scramble lipids by deforming the membrane near a hydrophilic groove and that Ca2+ dependence arises from the different association of lipids with an open or closed groove. However, the molecular rearrangements underlying groove opening and how lipids reorganize outside the closed groove remain unknown. Here we directly visualize how lipids associate at the closed groove of Ca2+-bound fungal nhTMEM16 in nanodiscs using cryo-EM. Functional experiments pinpoint lipid-protein interaction sites critical for closed groove scrambling. Structural and functional analyses suggest groove opening entails the sequential appearance of two π-helical turns in the groove-lining TM6 helix and identify critical rearrangements. Finally, we show that the choice of scaffold protein and lipids affects the conformations of nhTMEM16 and their distribution, highlighting a key role of these factors in cryo-EM structure determination.
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Affiliation(s)
- Zhang Feng
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, USA
| | - Omar E Alvarenga
- Physiology, Biophysics and Systems Biology Graduate Program, Weill Cornell Medical College, New York, NY, USA
| | - Alessio Accardi
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, USA.
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, USA.
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, USA.
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5
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Feng Z, Alvarenga OE, Accardi A. Structural basis of closed groove scrambling by a TMEM16 protein. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.11.553029. [PMID: 37609346 PMCID: PMC10441378 DOI: 10.1101/2023.08.11.553029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Activation of Ca2+-dependent TMEM16 scramblases induces the externalization of phosphatidylserine, a key molecule in multiple signaling processes. Current models suggest that the TMEM16s scramble lipids by deforming the membrane near a hydrophilic groove, and that Ca2+ dependence arises from the different association of lipids with an open or closed groove. However, the molecular rearrangements involved in groove opening and of how lipids reorganize outside the closed groove remain unknown. Using cryogenic electron microscopy, we directly visualize how lipids associate at the closed groove of Ca2+-bound nhTMEM16 in nanodiscs. Functional experiments pinpoint the lipid-protein interaction sites critical for closed groove scrambling. Structural and functional analyses suggest groove opening entails the sequential appearance of two π-helical turns in the groove-lining TM6 helix and identify critical rearrangements. Finally, we show that the choice of scaffold protein and lipids affects the conformations of nhTMEM16 and their distribution, highlighting a key role of these factors in cryoEM structure determination.
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Affiliation(s)
- Zhang Feng
- Department of Anesthesiology, Weill Cornell Medical College
| | - Omar E. Alvarenga
- Physiology, Biophysics and Systems Biology Graduate Program, Weill Cornell Medical College
| | - Alessio Accardi
- Department of Anesthesiology, Weill Cornell Medical College
- Department of Physiology and Biophysics, Weill Cornell Medical College
- Department of Biochemistry, Weill Cornell Medical College
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6
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Wakabayashi T, Oide M, Kato T, Nakasako M. Coenzyme-binding pathway on glutamate dehydrogenase suggested from multiple-binding sites visualized by cryo-electron microscopy. FEBS J 2023; 290:5514-5535. [PMID: 37682540 DOI: 10.1111/febs.16951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 08/10/2023] [Accepted: 09/05/2023] [Indexed: 09/09/2023]
Abstract
The structure of hexameric glutamate dehydrogenase (GDH) in the presence of the coenzyme nicotinamide adenine dinucleotide phosphate (NADP) was visualized using cryogenic transmission electron microscopy to investigate the ligand-binding pathways to the active site of the enzyme. Each subunit of GDH comprises one hexamer-forming core domain and one nucleotide-binding domain (NAD domain), which spontaneously opens and closes the active-site cleft situated between the two domains. In the presence of NADP, the potential map of GDH hexamer, assuming D3 symmetry, was determined at a resolution of 2.4 Å, but the NAD domain was blurred due to the conformational variety. After focused classification with respect to the NAD domain, the potential maps interpreted as NADP molecules appeared at five different sites in the active-site cleft. The subunits associated with NADP molecules were close to one of the four metastable conformations in the unliganded state. Three of the five binding sites suggested a pathway of NADP molecules to approach the active-site cleft for initiating the enzymatic reaction. The other two binding modes may rarely appear in the presence of glutamate, as demonstrated by the reaction kinetics. Based on the visualized structures and the results from the enzymatic kinetics, we discussed the binding modes of NADP to GDH in the absence and presence of glutamate.
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Grants
- JPMJPR22E2 Japan Science and Technology Agency
- 18J11653 Japan Society for the Promotion of Science
- jp13480214 Japan Society for the Promotion of Science
- jp19204042 Japan Society for the Promotion of Science
- jp21H01050 Japan Society for the Promotion of Science
- jp22244054 Japan Society for the Promotion of Science
- jp26800227 Japan Society for the Promotion of Science
- jp15076210 Ministry of Education, Culture, Sports, Science and Technology
- jp15H01647 Ministry of Education, Culture, Sports, Science and Technology
- jp17H05891 Ministry of Education, Culture, Sports, Science and Technology
- jp20050030 Ministry of Education, Culture, Sports, Science and Technology
- jp22018027 Ministry of Education, Culture, Sports, Science and Technology
- jp23120525 Ministry of Education, Culture, Sports, Science and Technology
- jp25120725 Ministry of Education, Culture, Sports, Science and Technology
- 0436 Japan Agency for Medical Research and Development
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Affiliation(s)
- Taiki Wakabayashi
- Department of Physics, Faculty of Science and Technology, Keio University, Yokohama, Japan
- RIKEN SPring-8 Center, Sayo-gun, Hyogo, Japan
- RIKEN Cluster for Pioneering Research, Wako, Japan
| | - Mao Oide
- Department of Physics, Faculty of Science and Technology, Keio University, Yokohama, Japan
- RIKEN SPring-8 Center, Sayo-gun, Hyogo, Japan
- RIKEN Cluster for Pioneering Research, Wako, Japan
- PRESTO, Japan Science and Technology Agency, Tokyo, Japan
| | - Takayuki Kato
- Protein Research Institute, Osaka University, Suita, Japan
| | - Masayoshi Nakasako
- Department of Physics, Faculty of Science and Technology, Keio University, Yokohama, Japan
- RIKEN SPring-8 Center, Sayo-gun, Hyogo, Japan
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7
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Miyashita O, Tama F. Advancing cryo-electron microscopy data analysis through accelerated simulation-based flexible fitting approaches. Curr Opin Struct Biol 2023; 82:102653. [PMID: 37451233 DOI: 10.1016/j.sbi.2023.102653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 05/30/2023] [Accepted: 06/19/2023] [Indexed: 07/18/2023]
Abstract
Flexible fitting based on molecular dynamics simulation is a technique for structure modeling from cryo-EM data. It has been utilized for nearly two decades, and while cryo-EM resolution has improved significantly, it remains a powerful approach that can provide structural and dynamical insights that are not directly accessible from experimental data alone. Molecular dynamics simulations provide a means to extract atomistic details of conformational changes that are encoded in cryo-EM data and can also assist in improving the quality of structural models. Additionally, molecular dynamics simulations enable the characterization of conformational heterogeneity in cryo-EM data. We will summarize the advancements made in these techniques and highlight recent developments in this field.
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Affiliation(s)
- Osamu Miyashita
- RIKEN Center for Computational Science, 6-7-1, Minatojima-minami-machi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
| | - Florence Tama
- RIKEN Center for Computational Science, 6-7-1, Minatojima-minami-machi, Chuo-ku, Kobe, Hyogo 650-0047, Japan; Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan; Institute of Transformative Bio-Molecules, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan.
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8
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Matsuura H, Sakai N, Toma-Fukai S, Muraki N, Hayama K, Kamikubo H, Aono S, Kawano Y, Yamamoto M, Hirata K. Elucidating polymorphs of crystal structures by intensity-based hierarchical clustering analysis of multiple diffraction data sets. Acta Crystallogr D Struct Biol 2023; 79:909-924. [PMID: 37747037 PMCID: PMC10565733 DOI: 10.1107/s2059798323007039] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Accepted: 08/07/2023] [Indexed: 09/26/2023] Open
Abstract
In macromolecular structure determination using X-ray diffraction from multiple crystals, the presence of different structures (structural polymorphs) necessitates the classification of the diffraction data for appropriate structural analysis. Hierarchical clustering analysis (HCA) is a promising technique that has so far been used to extract isomorphous data, mainly for single-structure determination. Although in principle the use of HCA can be extended to detect polymorphs, the absence of a reference to define the threshold used to group the isomorphous data sets (the `isomorphic threshold') poses a challenge. Here, unit-cell-based and intensity-based HCAs have been applied to data sets for apo trypsin and inhibitor-bound trypsin that were mixed post data acquisition to investigate the efficacy of HCA in classifying polymorphous data sets. Single-step intensity-based HCA successfully classified polymorphs with a certain `isomorphic threshold'. In data sets for several samples containing an unknown degree of structural heterogeneity, polymorphs could be identified by intensity-based HCA using the suggested `isomorphic threshold'. Polymorphs were also detected in single crystals using data collected using the continuous helical scheme. These findings are expected to facilitate the determination of multiple structural snapshots by exploiting automated data collection and analysis.
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Affiliation(s)
- Hiroaki Matsuura
- Life Science Research Infrastructure Group, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Naoki Sakai
- Life Science Research Infrastructure Group, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
- Structural Biology Division, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Sachiko Toma-Fukai
- Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
- Japan Agency for Medical Research and Development-Core Research for Evolutional Science and Technology (AMED-CREST), Tokyo 100-0004, Japan
| | - Norifumi Muraki
- Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- Exploratory Research Center on Life and Living Systems, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Koki Hayama
- Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
| | - Hironari Kamikubo
- Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
| | - Shigetoshi Aono
- Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
- Exploratory Research Center on Life and Living Systems, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan
| | - Yoshiaki Kawano
- Life Science Research Infrastructure Group, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Masaki Yamamoto
- Life Science Research Infrastructure Group, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
| | - Kunio Hirata
- Life Science Research Infrastructure Group, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198, Japan
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9
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Tang WS, Zhong ED, Hanson SM, Thiede EH, Cossio P. Conformational heterogeneity and probability distributions from single-particle cryo-electron microscopy. Curr Opin Struct Biol 2023; 81:102626. [PMID: 37311334 DOI: 10.1016/j.sbi.2023.102626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 04/25/2023] [Accepted: 05/16/2023] [Indexed: 06/15/2023]
Abstract
Single-particle cryo-electron microscopy (cryo-EM) is a technique that takes projection images of biomolecules frozen at cryogenic temperatures. A major advantage of this technique is its ability to image single biomolecules in heterogeneous conformations. While this poses a challenge for data analysis, recent algorithmic advances have enabled the recovery of heterogeneous conformations from the noisy imaging data. Here, we review methods for the reconstruction and heterogeneity analysis of cryo-EM images, ranging from linear-transformation-based methods to nonlinear deep generative models. We overview the dimensionality-reduction techniques used in heterogeneous 3D reconstruction methods and specify what information each method can infer from the data. Then, we review the methods that use cryo-EM images to estimate probability distributions over conformations in reduced subspaces or predefined by atomistic simulations. We conclude with the ongoing challenges for the cryo-EM community.
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Affiliation(s)
- Wai Shing Tang
- Center for Computational Mathematics, Flatiron Institute, 162 5th Ave, New York, NY, 10010, United States. https://twitter.com/WaiShingTang
| | - Ellen D Zhong
- Department of Computer Science, Princeton University, 35 Olden St, Princeton, NJ, 08544, United States. https://twitter.com/ZhongingAlong
| | - Sonya M Hanson
- Center for Computational Mathematics, Flatiron Institute, 162 5th Ave, New York, NY, 10010, United States; Center for Computational Biology, Flatiron Institute, 162 5th Ave, New York, NY, 10010, United States. https://twitter.com/sonyahans
| | - Erik H Thiede
- Center for Computational Mathematics, Flatiron Institute, 162 5th Ave, New York, NY, 10010, United States. https://twitter.com/erik_der_elch
| | - Pilar Cossio
- Center for Computational Mathematics, Flatiron Institute, 162 5th Ave, New York, NY, 10010, United States; Center for Computational Biology, Flatiron Institute, 162 5th Ave, New York, NY, 10010, United States.
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10
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Grzechowiak M, Sliwiak J, Jaskolski M, Ruszkowski M. Structural and functional studies of Arabidopsis thaliana glutamate dehydrogenase isoform 2 demonstrate enzyme dynamics and identify its calcium binding site. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2023; 201:107895. [PMID: 37478728 DOI: 10.1016/j.plaphy.2023.107895] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 06/26/2023] [Accepted: 07/12/2023] [Indexed: 07/23/2023]
Abstract
Glutamate dehydrogenase (GDH) is an enzyme at the crossroad of plant nitrogen and carbon metabolism. GDH catalyzes the conversion of 2-oxoglutarate into glutamate (2OG → Glu), utilizing ammonia as cosubstrate and NADH as coenzyme. The GDH reaction is reversible, meaning that the NAD+-dependent reaction (Glu → 2OG) releases ammonia. In Arabidopsis thaliana, three GDH isoforms exist, AtGDH1, AtGDH2, and AtGDH3. The subject of this work is AtGDH2. Previous reports have suggested that enzymes homologous to AtGDH2 contain a calcium-binding EF-hand motif located in the coenzyme binding domain. Here, we show that while AtGDH2 indeed does bind calcium, the binding occurs elsewhere and the region predicted to be the EF-hand motif has a completely different structure. As the true calcium binding site is > 20 Å away from the active site, it seems to play a structural, rather than catalytic role. We also performed comparative kinetic characterization of AtGDH1 and AtGDH2 using spectroscopic methods and isothermal titration calorimetry, to note that the isoenzymes generally exhibit similar behavior, with calcium having only a minor effect. However, the spatial and temporal changes in the gene expression profiles of the three AtGDH genes point to AtGDH2 as the most prevalent isoform.
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Affiliation(s)
- Marta Grzechowiak
- Department of Structural Biology of Eukaryotes, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, 61-704, Poland
| | - Joanna Sliwiak
- Laboratory of Protein Engineering, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, 61-704, Poland
| | - Mariusz Jaskolski
- Department of Structural Biology of Eukaryotes, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, 61-704, Poland; Department of Crystallography, Faculty of Chemistry, Adam Mickiewicz University, Poznan, 61-614, Poland
| | - Milosz Ruszkowski
- Department of Structural Biology of Eukaryotes, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznan, 61-704, Poland.
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11
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Blacker TS, Duchen MR, Bain AJ. NAD(P)H binding configurations revealed by time-resolved fluorescence and two-photon absorption. Biophys J 2023; 122:1240-1253. [PMID: 36793214 PMCID: PMC10111271 DOI: 10.1016/j.bpj.2023.02.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 09/07/2022] [Accepted: 02/10/2023] [Indexed: 02/16/2023] Open
Abstract
NADH and NADPH play key roles in the regulation of metabolism. Their endogenous fluorescence is sensitive to enzyme binding, allowing changes in cellular metabolic state to be determined using fluorescence lifetime imaging microscopy (FLIM). However, to fully uncover the underlying biochemistry, the relationships between their fluorescence and binding dynamics require greater understanding. Here we accomplish this through time- and polarization-resolved fluorescence and polarized two-photon absorption measurements. Two lifetimes result from binding of both NADH to lactate dehydrogenase and NADPH to isocitrate dehydrogenase. The composite fluorescence anisotropy indicates the shorter (1.3-1.6 ns) decay component to be accompanied by local motion of the nicotinamide ring, pointing to attachment solely via the adenine moiety. For the longer lifetime (3.2-4.4 ns), the nicotinamide conformational freedom is found to be fully restricted. As full and partial nicotinamide binding are recognized steps in dehydrogenase catalysis, our results unify photophysical, structural, and functional aspects of NADH and NADPH binding and clarify the biochemical processes that underlie their contrasting intracellular lifetimes.
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Affiliation(s)
- Thomas S Blacker
- Department of Physics & Astronomy, University College London, London, United Kingdom; Research Department of Cell & Developmental Biology, University College London, London, United Kingdom
| | - Michael R Duchen
- Research Department of Cell & Developmental Biology, University College London, London, United Kingdom
| | - Angus J Bain
- Department of Physics & Astronomy, University College London, London, United Kingdom.
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12
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Luque D, Ortega-Esteban A, Valbuena A, Luis Vilas J, Rodríguez-Huete A, Mateu MG, Castón JR. Equilibrium Dynamics of a Biomolecular Complex Analyzed at Single-amino Acid Resolution by Cryo-electron Microscopy. J Mol Biol 2023; 435:168024. [PMID: 36828271 DOI: 10.1016/j.jmb.2023.168024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 02/10/2023] [Accepted: 02/17/2023] [Indexed: 02/24/2023]
Abstract
The biological function of macromolecular complexes depends not only on large-scale transitions between conformations, but also on small-scale conformational fluctuations at equilibrium. Information on the equilibrium dynamics of biomolecular complexes could, in principle, be obtained from local resolution (LR) data in cryo-electron microscopy (cryo-EM) maps. However, this possibility had not been validated by comparing, for a same biomolecular complex, LR data with quantitative information on equilibrium dynamics obtained by an established solution technique. In this study we determined the cryo-EM structure of the minute virus of mice (MVM) capsid as a model biomolecular complex. The LR values obtained correlated with crystallographic B factors and with hydrogen/deuterium exchange (HDX) rates obtained by mass spectrometry (HDX-MS), a gold standard for determining equilibrium dynamics in solution. This result validated a LR-based cryo-EM approach to investigate, with high spatial resolution, the equilibrium dynamics of biomolecular complexes. As an application of this approach, we determined the cryo-EM structure of two mutant MVM capsids and compared their equilibrium dynamics with that of the wild-type MVM capsid. The results supported a previously suggested linkage between mechanical stiffening and impaired equilibrium dynamics of a virus particle. Cryo-EM is emerging as a powerful approach for simultaneously acquiring information on the atomic structure and local equilibrium dynamics of biomolecular complexes.
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Affiliation(s)
- Daniel Luque
- Spanish National Microbiology Centre, Institute of Health Carlos III, Madrid, Spain
| | - Alvaro Ortega-Esteban
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid, Spain
| | - Alejandro Valbuena
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
| | - Jose Luis Vilas
- Biocomputing Unit, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid, Spain
| | - Alicia Rodríguez-Huete
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain
| | - Mauricio G Mateu
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain.
| | - José R Castón
- Department of Structure of Macromolecules, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid, Spain.
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13
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Sato K, Oide M, Nakasako M. Prediction of hydrophilic and hydrophobic hydration structure of protein by neural network optimized using experimental data. Sci Rep 2023; 13:2183. [PMID: 36750742 PMCID: PMC9905073 DOI: 10.1038/s41598-023-29442-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 02/06/2023] [Indexed: 02/09/2023] Open
Abstract
The hydration structures of proteins, which are necessary for their folding, stability, and functions, were visualized using X-ray and neutron crystallography and transmission electron microscopy. However, complete visualization of hydration structures over the entire protein surface remains difficult. To compensate for this incompleteness, we developed a three-dimensional convolutional neural network to predict the probability distribution of hydration water molecules on the hydrophilic and hydrophobic surfaces, and in the cavities of proteins. The neural network was optimized using the distribution patterns of protein atoms around the hydration water molecules identified in the high-resolution X-ray crystal structures. We examined the feasibility of the neural network using water sites in the protein crystal structures that were not included in the datasets. The predicted distribution covered most of the experimentally identified hydration sites, with local maxima appearing in their vicinity. This computational approach will help to highlight the relevance of hydration structures to the biological functions and dynamics of proteins.
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Affiliation(s)
- Kochi Sato
- Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, 223-8522, Japan.,RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5148, Japan
| | - Mao Oide
- Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, 223-8522, Japan.,RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5148, Japan.,PRESTO, Japan Science and Technology Agency, Chiyoda-ku, Tokyo, 102-0076, Japan
| | - Masayoshi Nakasako
- Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa, 223-8522, Japan. .,RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo, 679-5148, Japan.
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14
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Meng X, Liu Y, Yang L, Li R, Wang H, Shen Y, Wei D. Rational identification of a high catalytic efficiency leucine dehydrogenase and process development for efficient synthesis of l-phenylglycine. Biotechnol J 2023; 18:e2200465. [PMID: 36738237 DOI: 10.1002/biot.202200465] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 01/01/2023] [Accepted: 02/02/2023] [Indexed: 02/05/2023]
Abstract
Enzymatic asymmetric synthesis of chiral amino acids has great industrial potential. However, the low catalytic efficiency of high-concentration substrates limits their industrial application. Herein, using a combination of substrate catalytic efficiency prediction based on "open to closed" conformational change and substrate specificity prediction, a novel leucine dehydrogenase (TsLeuDH), with high substrate catalytic efficiency toward benzoylformic acid (BFA) for producing l-phenylglycine (l-Phg), was directly identified from 4695 putative leucine dehydrogenases in a public database. The specific activity of TsLeuDH was determined to be as high as 4253.8 U mg-1 . Through reaction process optimization, a high-concentration substrate (0.7 m) was efficiently and completely converted within 90 min in a single batch, without any external coenzyme addition. Moreover, a continuous flow-feeding approach was designed using gradient control of the feed rate to reduce substrate accumulation. Finally, the highest overall substrate concentration of up to 1.2 m BFA could be aminated to l-Phg with conversion of >99% in 3 h, demonstrating that this new combination of enzyme process development is promising for large-scale application of l-Phg.
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Affiliation(s)
- Xiangqi Meng
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People's Republic of China
| | - Yan Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People's Republic of China
| | - Lin Yang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People's Republic of China
| | - Rui Li
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People's Republic of China
| | - Hualei Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People's Republic of China
| | - Yaling Shen
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People's Republic of China
| | - Dongzhi Wei
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People's Republic of China
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15
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Beton JG, Cragnolini T, Kaleel M, Mulvaney T, Sweeney A, Topf M. Integrating model simulation tools and
cryo‐electron
microscopy. WIRES COMPUTATIONAL MOLECULAR SCIENCE 2022. [DOI: 10.1002/wcms.1642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Joseph George Beton
- Centre for Structural Systems Biology (CSSB) Leibniz‐Institut für Virologie (LIV) Hamburg Germany
| | - Tristan Cragnolini
- Institute of Structural and Molecular Biology, Birkbeck and University College London London UK
| | - Manaz Kaleel
- Centre for Structural Systems Biology (CSSB) Leibniz‐Institut für Virologie (LIV) Hamburg Germany
| | - Thomas Mulvaney
- Centre for Structural Systems Biology (CSSB) Leibniz‐Institut für Virologie (LIV) Hamburg Germany
| | - Aaron Sweeney
- Centre for Structural Systems Biology (CSSB) Leibniz‐Institut für Virologie (LIV) Hamburg Germany
| | - Maya Topf
- Centre for Structural Systems Biology (CSSB) Leibniz‐Institut für Virologie (LIV) Hamburg Germany
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16
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Yagi K, Re S, Mori T, Sugita Y. Weight average approaches for predicting dynamical properties of biomolecules. Curr Opin Struct Biol 2021; 72:88-94. [PMID: 34592697 DOI: 10.1016/j.sbi.2021.08.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 08/21/2021] [Accepted: 08/24/2021] [Indexed: 11/16/2022]
Abstract
Recent advances in atomistic molecular dynamics (MD) simulations of biomolecules allow us to explore their conformational spaces widely, observing large-scale conformational fluctuations or transitions between distinct structures. To reproduce or refine experimental data using MD simulations, structure ensembles, which are characterized by multiple structures and their statistical weights on the rugged free-energy landscapes, are often used. Here, we summarize weight average approaches for various experimental measurements. Weight average approaches are now applied to hybrid quantum mechanics/molecular mechanics MD simulations to predict fast vibrational motions in a protein with a high accuracy for better understanding of molecular functions from atomic structures.
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Affiliation(s)
- Kiyoshi Yagi
- RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Suyong Re
- RIKEN Center for Biosystems Dynamics Research, 1-6-5 Minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan; Artificial Intelligence Center for Health and Biomedical Research, National Institutes of Biomedical Innovation, Health, and Nutrition 7-6-8, Saito-Asagi, Ibaraki, Osaka, 567-0085, Japan
| | - Takaharu Mori
- RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yuji Sugita
- RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; RIKEN Center for Biosystems Dynamics Research, 1-6-5 Minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan; RIKEN Center for Computational Science, 7-1-26 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
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17
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Multiscale simulations of large complexes in conjunction with cryo-EM analysis. Curr Opin Struct Biol 2021; 72:27-32. [PMID: 34399155 DOI: 10.1016/j.sbi.2021.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/15/2021] [Accepted: 07/16/2021] [Indexed: 11/21/2022]
Abstract
The cellular environment is highly crowded with most proteins and RNA/DNA forming homomeric and heteromeric complexes. Essential questions regarding how these complexes switch between functional, rest, and abnormal states with regulators or modifications remain challenging and complicated. Here, we review the recent progress integrating cryoelectron microscopy and multiscale molecular modeling to understand the dynamics and function-related mechanism in protein-RNA/DNA complexes, protein-protein complexes/assemblies, and membrane protein complexes. One future direction of multiscale simulations will be to interpret the large complex multibody regulation in assembly-induced function enhancement in conjunction with advanced atomic resolution structural-biology techniques and specialized computing architectures.
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18
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Giraldo-Barreto J, Ortiz S, Thiede EH, Palacio-Rodriguez K, Carpenter B, Barnett AH, Cossio P. A Bayesian approach to extracting free-energy profiles from cryo-electron microscopy experiments. Sci Rep 2021; 11:13657. [PMID: 34211017 PMCID: PMC8249403 DOI: 10.1038/s41598-021-92621-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 06/01/2021] [Indexed: 11/08/2022] Open
Abstract
Cryo-electron microscopy (cryo-EM) extracts single-particle density projections of individual biomolecules. Although cryo-EM is widely used for 3D reconstruction, due to its single-particle nature it has the potential to provide information about a biomolecule's conformational variability and underlying free-energy landscape. However, treating cryo-EM as a single-molecule technique is challenging because of the low signal-to-noise ratio (SNR) in individual particles. In this work, we propose the cryo-BIFE method (cryo-EM Bayesian Inference of Free-Energy profiles), which uses a path collective variable to extract free-energy profiles and their uncertainties from cryo-EM images. We test the framework on several synthetic systems where the imaging parameters and conditions were controlled. We found that for realistic cryo-EM environments and relevant biomolecular systems, it is possible to recover the underlying free energy, with the pose accuracy and SNR as crucial determinants. We then use the method to study the conformational transitions of a calcium-activated channel with real cryo-EM particles. Interestingly, we recover not only the most probable conformation (used to generate a high-resolution reconstruction of the calcium-bound state) but also a metastable state that corresponds to the calcium-unbound conformation. As expected for turnover transitions within the same sample, the activation barriers are on the order of [Formula: see text]. We expect our tool for extracting free-energy profiles from cryo-EM images to enable more complete characterization of the thermodynamic ensemble of biomolecules.
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Affiliation(s)
- Julian Giraldo-Barreto
- Biophysics of Tropical Diseases Max Planck Tandem Group, University of Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia
- Magnetism and Simulation Group, University of Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia
| | - Sebastian Ortiz
- Biophysics of Tropical Diseases Max Planck Tandem Group, University of Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia
| | - Erik H Thiede
- Center for Computational Mathematics, Flatiron Institute, New York City, USA
| | - Karen Palacio-Rodriguez
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Université, Paris, France
| | - Bob Carpenter
- Center for Computational Mathematics, Flatiron Institute, New York City, USA
| | - Alex H Barnett
- Center for Computational Mathematics, Flatiron Institute, New York City, USA
| | - Pilar Cossio
- Biophysics of Tropical Diseases Max Planck Tandem Group, University of Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia.
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, 60438, Frankfurt am Main, Germany.
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19
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Wang Z, Zhang Q, Mim C. Coming of Age: Cryo-Electron Tomography as a Versatile Tool to Generate High-Resolution Structures at Cellular/Biological Interfaces. Int J Mol Sci 2021; 22:6177. [PMID: 34201105 PMCID: PMC8228724 DOI: 10.3390/ijms22126177] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/01/2021] [Accepted: 06/02/2021] [Indexed: 12/29/2022] Open
Abstract
Over the last few years, cryo electron microscopy has become the most important method in structural biology. While 80% of deposited maps are from single particle analysis, electron tomography has grown to become the second most important method. In particular sub-tomogram averaging has matured as a method, delivering structures between 2 and 5 Å from complexes in cells as well as in vitro complexes. While this resolution range is not standard, novel developments point toward a promising future. Here, we provide a guide for the workflow from sample to structure to gain insight into this emerging field.
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Affiliation(s)
| | | | - Carsten Mim
- Department of Biomedical Engineering and Health Systems, Royal Technical Institute (KTH), Hälsovägen 11C, 141 27 Huddinge, Sweden; (Z.W.); (Q.Z.)
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20
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Zhao Y, Gao J, Su S, Shan X, Li S, Liu H, Yuan Y, Li H. Regulation of the activity of maize glutamate dehydrogenase by ammonium and potassium. Biosci Biotechnol Biochem 2021; 85:262-271. [PMID: 33604622 DOI: 10.1093/bbb/zbaa020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 08/18/2020] [Indexed: 11/14/2022]
Abstract
Glutamate dehydrogenase (GDH) is an important enzyme in ammonium metabolism, the activity of which is regulated by multiple factors. In this study, we investigate the effects of ammonium and potassium on the activity of maize GDH. Our results show that both ammonium and potassium play multiple roles in regulating the activity of maize GDH, with the specific roles depending on the concentration of potassium. Together with the structural information of GDH, we propose models for the substrate inhibition of ammonium, and the elimination of substrate inhibition by potassium. These models are supported by the analysis of statistic thermodynamics. We also analyze the binding sites of ammonium and potassium on maize GDH, and the conformational changes of maize GDH. The findings provide insight into the regulation of maize GDH activity by ammonium and potassium and reveal the importance of the dose and ratio of nitrogen and potassium in crop cultivation.
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Affiliation(s)
- Yanjie Zhao
- College of Plant Science, Jilin University, Changchun, China
| | - Jie Gao
- College of Plant Science, Jilin University, Changchun, China
| | - Shengzhong Su
- College of Plant Science, Jilin University, Changchun, China
| | - Xiaohui Shan
- College of Plant Science, Jilin University, Changchun, China
| | - Shipeng Li
- College of Plant Science, Jilin University, Changchun, China
| | - Hongkui Liu
- College of Plant Science, Jilin University, Changchun, China
| | - Yaping Yuan
- College of Plant Science, Jilin University, Changchun, China
| | - He Li
- College of Plant Science, Jilin University, Changchun, China
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21
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Oroguchi T, Oide M, Wakabayashi T, Nakasako M. Assessment of Force Field Accuracy Using Cryogenic Electron Microscopy Data of Hyper-thermostable Glutamate Dehydrogenase. J Phys Chem B 2020; 124:8479-8494. [PMID: 32841031 DOI: 10.1021/acs.jpcb.0c04464] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Molecular dynamics (MD) simulations in biophysically relevant time scales of microseconds is a powerful tool for studying biomolecular processes, but results often display force field dependency. Therefore, assessment of force field accuracy using experimental data of biomolecules in solution is essential for simulation studies. Here, we propose the use of structural models obtained via cryo-electron microscopy (cryoEM), which provides biomolecular structures in vitreous ice mimicking the environment in solution. The accuracy of the AMBER (ff99SB-ILDN-NMR, ff14SB, ff15ipq, and ff15FB) and CHARMM (CHARMM22 and CHARMM36m) force fields was assessed by comparing their MD trajectories with the cryoEM data of thermostable hexameric glutamate dehydrogenase (GDH), which included a cryoEM map at a resolution of approximately 3 Å and structure models of subunits reflecting metastable conformations in domain motion occurring in GDH. In the assessment, we validated the force fields with respect to the reproducibility and stability of secondary structures and intersubunit interactions in the cryoEM data. Furthermore, we evaluated the force fields regarding the reproducibility of the energy landscape in the domain motion expected from the cryoEM data. As a result, among the six force fields, ff15FB and ff99SB-ILDN-NMR displayed good agreement with the experiment. The present study demonstrated the advantages of the high-resolution cryoEM map and suggested the optimal force field to reproduce experimentally observed protein structures.
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Affiliation(s)
- Tomotaka Oroguchi
- Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoko-ku, Yokohama, Kanagawa 223-8522, Japan.,RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Mao Oide
- Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoko-ku, Yokohama, Kanagawa 223-8522, Japan.,RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Taiki Wakabayashi
- Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoko-ku, Yokohama, Kanagawa 223-8522, Japan.,RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Masayoshi Nakasako
- Department of Physics, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoko-ku, Yokohama, Kanagawa 223-8522, Japan.,RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
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22
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Domain Organization in Plant Blue-Light Receptor Phototropin2 of Arabidopsis thaliana Studied by Small-Angle X-ray Scattering. Int J Mol Sci 2020; 21:ijms21186638. [PMID: 32927860 PMCID: PMC7555306 DOI: 10.3390/ijms21186638] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/06/2020] [Accepted: 09/07/2020] [Indexed: 01/10/2023] Open
Abstract
Phototropin2 (phot2) is a blue-light (BL) receptor protein that regulates the BL-dependent activities of plants for efficient photosynthesis. Phot2 is composed of two light-oxygen-voltage sensing domains (LOV1 and LOV2) to absorb BL, and a kinase domain. Photo-activated LOV domains, especially LOV2, play a major role in photo-dependent increase in the phosphorylation activity of the kinase domain. The atomic details of the overall structure of phot2 and the intramolecular mechanism to convert BL energy to a phosphorylation signal remain unknown. We performed structural studies on the LOV fragments LOV1, LOV2, LOV2-linker, and LOV2-kinase, and full-length phot2, using small-angle X-ray scattering (SAXS). The aim of the study was to understand structural changes under BL irradiation and discuss the molecular mechanism that enhance the phosphorylation activity under BL. SAXS is a suitable technique for visualizing molecular structures of proteins in solution at low resolution and is advantageous for monitoring their structural changes in the presence of external physical and/or chemical stimuli. Structural parameters and molecular models of the recombinant specimens were obtained from SAXS profiles in the dark, under BL irradiation, and after dark reversion. LOV1, LOV2, and LOV2-linker fragments displayed minimal structural changes. However, BL-induced rearrangements of functional domains were noted for LOV2-kinase and full-length phot2. Based on the molecular model together with the absorption measurements and biochemical assays, we discuss the intramolecular interactions and domain motions necessary for BL-enhanced phosphorylation activity of phot2.
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23
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Grzechowiak M, Sliwiak J, Jaskolski M, Ruszkowski M. Structural Studies of Glutamate Dehydrogenase (Isoform 1) From Arabidopsis thaliana, an Important Enzyme at the Branch-Point Between Carbon and Nitrogen Metabolism. FRONTIERS IN PLANT SCIENCE 2020; 11:754. [PMID: 32655590 PMCID: PMC7326016 DOI: 10.3389/fpls.2020.00754] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 05/12/2020] [Indexed: 05/24/2023]
Abstract
Glutamate dehydrogenase (GDH) releases ammonia in a reversible NAD(P)+-dependent oxidative deamination of glutamate that yields 2-oxoglutarate (2OG). In current perception, GDH contributes to Glu homeostasis and plays a significant role at the junction of carbon and nitrogen assimilation pathways. GDHs are members of a superfamily of ELFV (Glu/Leu/Phe/Val) amino acid dehydrogenases and are subdivided into three subclasses, based on coenzyme specificity: NAD+-specific, NAD+/NADP+ dual-specific, and NADP+-specific. We determined in this work that the mitochondrial AtGDH1 isozyme from A. thaliana is NAD+-specific. Altogether, A. thaliana expresses three GDH isozymes (AtGDH1-3) targeted to mitochondria, of which AtGDH2 has an extra EF-hand motif and is stimulated by calcium. Our enzymatic assays of AtGDH1 established that its sensitivity to calcium is negligible. In vivo the AtGDH1-3 enzymes form homo- and heterohexamers of varied composition. We solved the crystal structure of recombinant AtGDH1 in the apo-form and in complex with NAD+ at 2.59 and 2.03 Å resolution, respectively. We demonstrate also that both in the apo form and in 1:1 complex with NAD+, it forms D 3-symmetric homohexamers. A subunit of AtGDH1 consists of domain I, which is involved in hexamer formation and substrate binding, and of domain II which binds coenzyme. Most of the subunits in our crystal structures, including those in NAD+ complex, are in open conformation, with domain II forming a large (albeit variable) angle with domain I. One of the subunits of the AtGDH1-NAD+ hexamer contains a serendipitous 2OG molecule in the active site, causing a dramatic (∼25°) closure of the domains. We provide convincing evidence that the N-terminal peptide preceding domain I is a mitochondrial targeting signal, with a predicted cleavage site for mitochondrial processing peptidase (MPP) at Leu17-Leu18 that is followed by an unexpected potassium coordination site (Ser27, Ile30). We also identified several MPD [(+/-)-2-methyl-2,4-pentanediol] binding sites with conserved sequence. Although AtGDH1 is insensitive to MPD in our assays, the observation of druggable sites opens a potential for non-competitive herbicide design.
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Affiliation(s)
- Marta Grzechowiak
- Center for Biocrystallographic Research Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland
| | - Joanna Sliwiak
- Center for Biocrystallographic Research Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland
| | - Mariusz Jaskolski
- Center for Biocrystallographic Research Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland
- Department of Crystallography, Faculty of Chemistry, Adam Mickiewicz University, Poznań, Poland
| | - Milosz Ruszkowski
- Center for Biocrystallographic Research Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland
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