1
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Nagahata Y, Kobayashi M, Toda M, Maeda S, Taketsugu T, Komatsuzaki T. An encompassed representation of timescale hierarchies in first-order reaction network. Proc Natl Acad Sci U S A 2024; 121:e2317781121. [PMID: 38758700 PMCID: PMC11126998 DOI: 10.1073/pnas.2317781121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 04/16/2024] [Indexed: 05/19/2024] Open
Abstract
Complex networks are pervasive in various fields such as chemistry, biology, and sociology. In chemistry, first-order reaction networks are represented by a set of first-order differential equations, which can be constructed from the underlying energy landscape. However, as the number of nodes increases, it becomes more challenging to understand complex kinetics across different timescales. Hence, how to construct an interpretable, coarse-graining scheme that preserves the underlying timescales of overall reactions is of crucial importance. Here, we develop a scheme to capture the underlying hierarchical subsets of nodes, and a series of coarse-grained (reduced-dimensional) rate equations between the subsets as a function of time resolution from the original reaction network. Each of the coarse-grained representations guarantees to preserve the underlying slow characteristic timescales in the original network. The crux is the construction of a lumping scheme incorporating a similarity measure in deciphering the underlying timescale hierarchy, which does not rely on the assumption of equilibrium. As an illustrative example, we apply the scheme to four-state Markovian models and Claisen rearrangement of allyl vinyl ether (AVE), and demonstrate that the reduced-dimensional representation accurately reproduces not only the slowest but also the faster timescales of overall reactions although other reduction schemes based on equilibrium assumption well reproduce the slowest timescale but fail to reproduce the second-to-fourth slowest timescales with the same accuracy. Our scheme can be applied not only to the reaction networks but also to networks in other fields, which helps us encompass their hierarchical structures of the complex kinetics over timescales.
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Affiliation(s)
- Yutaka Nagahata
- The Institute for Chemical Reaction Design and Discovery, Hokkaido University, Sapporo001-0021, Japan
- Research Center of Mathematics for Social Creativity, Research Institute for Electronic Science, Hokkaido University, Sapporo001-0020, Japan
| | - Masato Kobayashi
- The Institute for Chemical Reaction Design and Discovery, Hokkaido University, Sapporo001-0021, Japan
- Research Center of Mathematics for Social Creativity, Research Institute for Electronic Science, Hokkaido University, Sapporo001-0020, Japan
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo060-0810, Japan
| | - Mikito Toda
- Research Center of Mathematics for Social Creativity, Research Institute for Electronic Science, Hokkaido University, Sapporo001-0020, Japan
- Faculty Division of Natural Sciences, Nara Women’s University, Nara630-8506, Japan
- Graduate School of Information Science, University of Hyogo, Kobe650-0047, Japan
| | - Satoshi Maeda
- The Institute for Chemical Reaction Design and Discovery, Hokkaido University, Sapporo001-0021, Japan
- Research Center of Mathematics for Social Creativity, Research Institute for Electronic Science, Hokkaido University, Sapporo001-0020, Japan
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo060-0810, Japan
| | - Tetsuya Taketsugu
- The Institute for Chemical Reaction Design and Discovery, Hokkaido University, Sapporo001-0021, Japan
- Research Center of Mathematics for Social Creativity, Research Institute for Electronic Science, Hokkaido University, Sapporo001-0020, Japan
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo060-0810, Japan
| | - Tamiki Komatsuzaki
- The Institute for Chemical Reaction Design and Discovery, Hokkaido University, Sapporo001-0021, Japan
- Research Center of Mathematics for Social Creativity, Research Institute for Electronic Science, Hokkaido University, Sapporo001-0020, Japan
- Institute for Open and Transdisciplinary Research Initiatives, Osaka University, Suita565-0871, Japan
- The Institute of Scientific and Industrial Research, Osaka University, Ibaraki567-0047, Japan
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2
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Mazal H, Haran G. Single-molecule FRET methods to study the dynamics of proteins at work. CURRENT OPINION IN BIOMEDICAL ENGINEERING 2019; 12:8-17. [PMID: 31989063 PMCID: PMC6984960 DOI: 10.1016/j.cobme.2019.08.007] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Feynman commented that "Everything that living things do can be understood in terms of the jiggling and wiggling of atoms". Proteins can jiggle and wiggle large structural elements such as domains and subunits as part of their functional cycles. Single-molecule fluorescence resonance energy transfer (smFRET) is an excellent tool to study conformational dynamics and decipher coordinated large-scale motions within proteins. smFRET methods introduced in recent years are geared toward understanding the time scales and amplitudes of function-related motions. This review discusses the methodology for obtaining and analyzing smFRET temporal trajectories that provide direct dynamic information on transitions between conformational states. It also introduces correlation methods that are useful for characterizing intramolecular motions. This arsenal of techniques has been used to study multiple molecular systems, from membrane proteins through molecular chaperones, and we examine some of these studies here. Recent exciting methodological novelties permit revealing very fast, submillisecond dynamics, whose relevance to protein function is yet to be fully grasped.
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Affiliation(s)
- Hisham Mazal
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Gilad Haran
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
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3
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Helal KM, Taylor JN, Cahyadi H, Okajima A, Tabata K, Itoh Y, Tanaka H, Fujita K, Harada Y, Komatsuzaki T. Raman spectroscopic histology using machine learning for nonalcoholic fatty liver disease. FEBS Lett 2019; 593:2535-2544. [PMID: 31254349 DOI: 10.1002/1873-3468.13520] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 06/03/2019] [Accepted: 06/27/2019] [Indexed: 01/01/2023]
Abstract
Histopathology requires the expertise of specialists to diagnose morphological features of cells and tissues. Raman imaging can provide additional biochemical information to benefit histological disease diagnosis. Using a dietary model of nonalcoholic fatty liver disease in rats, we combine Raman imaging with machine learning and information theory to evaluate cellular-level information in liver tissue samples. After increasing signal-to-noise ratio in the Raman images through superpixel segmentation, we extract biochemically distinct regions within liver tissues, allowing for quantification of characteristic biochemical components such as vitamin A and lipids. Armed with microscopic information about the biochemical composition of the liver tissues, we group tissues having similar composition, providing a descriptor enabling inference of tissue states, contributing valuable information to histological inspection.
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Affiliation(s)
- Khalifa Mohammad Helal
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan.,Department of Mathematics, Comilla University, Cumilla, Bangladesh
| | - James Nicholas Taylor
- Research Center of Mathematics for Social Creativity, Institute for Electronic Science, Hokkaido University, Sapporo, Japan
| | - Harsono Cahyadi
- Department of Pathology and Cell Regulation, Kyoto Prefectural University of Medicine, Japan
| | - Akira Okajima
- Department of Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Japan
| | - Koji Tabata
- Research Center of Mathematics for Social Creativity, Institute for Electronic Science, Hokkaido University, Sapporo, Japan
| | - Yoshito Itoh
- Department of Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Japan
| | - Hideo Tanaka
- Department of Pathology and Cell Regulation, Kyoto Prefectural University of Medicine, Japan
| | - Katsumasa Fujita
- Department of Applied Physics, Osaka University, Japan.,Transdimensional Life Imaging Division, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, Japan.,Advanced Photonics and Biosensing Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology, Osaka University, Japan
| | - Yoshinori Harada
- Department of Pathology and Cell Regulation, Kyoto Prefectural University of Medicine, Japan
| | - Tamiki Komatsuzaki
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan.,Research Center of Mathematics for Social Creativity, Institute for Electronic Science, Hokkaido University, Sapporo, Japan.,Institute for Chemical Reaction Design and Discovery, Hokkaido University, Sapporo, Japan.,Laboratoire Interdisciplinaire Carnot de Bourgogne, Université de Bourgogne, Dijon, France
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4
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Taylor JN, Mochizuki K, Hashimoto K, Kumamoto Y, Harada Y, Fujita K, Komatsuzaki T. High-Resolution Raman Microscopic Detection of Follicular Thyroid Cancer Cells with Unsupervised Machine Learning. J Phys Chem B 2019; 123:4358-4372. [PMID: 31035762 DOI: 10.1021/acs.jpcb.9b01159] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We use Raman microscopic images with high spatial and spectral resolution to investigate differences between human follicular thyroid (Nthy-ori 3-1) and follicular thyroid carcinoma (FTC-133) cells, a well-differentiated thyroid cancer. Through comparison to classification of single-cell Raman spectra, the importance of subcellular information in the Raman images is emphasized. Subcellular information is extracted through a coarse-graining of the spectra at high spatial resolution (∼1.7 μm2), producing a set of characteristic spectral groups representing locations having similar biochemical compositions. We develop a cell classifier based on the frequencies at which the characteristic spectra appear within each of the single cells. Using this classifier, we obtain a more accurate (89.8%) distinction of FTC-133 and Nthy-ori 3-1, in comparison to single-cell spectra (77.6%). We also infer which subcellular components are important to cellular distinction; we find that cancerous FTC-133 cells contain increased populations of lipid-containing components and decreased populations of cytochrome-containing components relative to Nthy-ori 3-1, and that the regions containing these contributions are largely outside the cell nuclei. In addition to increased classification accuracy, this approach provides rich subcellular information about biochemical differences and cellular locations associated with the distinction of the normal and cancerous follicular thyroid cells.
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Affiliation(s)
- J Nicholas Taylor
- Research Institute for Electronic Science , Hokkaido University , Kita 20, Nishi 10 , Kita-ku, Sapporo 001-0020 , Japan
| | - Kentaro Mochizuki
- Department of Applied Physics , Osaka University , 2-1 Yamadaoka , Suita, Osaka 565-0871 , Japan
| | - Kosuke Hashimoto
- Department of Pathology and Cell Regulation, Graduate School of Medical Science , Kyoto Prefectural University of Medicine , Kajii-cho, Kawaramachi-Hirokoji, Kyoto , 602-8566 , Japan
| | - Yasuaki Kumamoto
- Department of Pathology and Cell Regulation, Graduate School of Medical Science , Kyoto Prefectural University of Medicine , Kajii-cho, Kawaramachi-Hirokoji, Kyoto , 602-8566 , Japan
| | - Yoshinori Harada
- Department of Pathology and Cell Regulation, Graduate School of Medical Science , Kyoto Prefectural University of Medicine , Kajii-cho, Kawaramachi-Hirokoji, Kyoto , 602-8566 , Japan
| | - Katsumasa Fujita
- Department of Applied Physics , Osaka University , 2-1 Yamadaoka , Suita, Osaka 565-0871 , Japan.,Advanced Photonics and Biosensing Open Innovation Laboratory , AIST-Osaka University , Yamadaoka , Suita, Osaka 565-0871 , Japan.,Transdimensional Life Imaging Division, Institute for Open and Transdisciplinary Research Initiatives , Osaka University , Yamadaoka , Suita, Osaka 565-0871 , Japan
| | - Tamiki Komatsuzaki
- Research Institute for Electronic Science , Hokkaido University , Kita 20, Nishi 10 , Kita-ku, Sapporo 001-0020 , Japan.,Institute for Chemical Reaction Design and Discovery (WPI-ICReDD) , Hokkaido University , Kita 21 Nishi 10 , Kita-ku, Sapporo , Hokkaido 001-0021 , Japan.,Laboratoire Interdisciplinaire Carnot de Bourgogne , UMR 6303 CNRS-Université Bourgogne Franche-Comt , 9 Avenue A. Savary, BP 47 870 , F-21078 , Dijon Cedex , France
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5
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Chatterjee S, Ade C, Nurik CE, Carrejo NC, Dutta C, Jayaraman V, Landes CF. Phosphorylation Induces Conformational Rigidity at the C-Terminal Domain of AMPA Receptors. J Phys Chem B 2019; 123:130-137. [PMID: 30537817 DOI: 10.1021/acs.jpcb.8b10749] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The intracellular C-terminal domain (CTD) of AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor undergoes phosphorylation at specific locations during long-term potentiation. This modification enhances conductance through the AMPA receptor ion channel and thus potentially plays a crucial role in modulating receptor trafficking and signaling. However, because the CTD structure is largely unresolved, it is difficult to establish if phosphorylation induces conformational changes that might play a role in enhancing channel conductance. Herein, we utilize single-molecule Förster resonance energy transfer (smFRET) spectroscopy to probe the conformational changes of a section of the AMPA receptor CTD, under the conditions of point-mutated phosphomimicry. Multiple analysis algorithms fail to identify stable conformational states within the smFRET distributions, consistent with a lack of well-defined secondary structure. Instead, our results show that phosphomimicry induces conformational rigidity to the CTD, and such rigidity is electrostatically tunable.
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Affiliation(s)
- Sudeshna Chatterjee
- Department of Chemistry , Rice University , Houston , Texas 77005 , United States
| | - Carina Ade
- Department of Chemistry , Rice University , Houston , Texas 77005 , United States
| | - Caitlin E Nurik
- Department of Biochemistry and Molecular Biology , University of Texas Health Medical School , Houston , Texas 77005 , United States
| | - Nicole C Carrejo
- Department of Chemistry , Rice University , Houston , Texas 77005 , United States
| | - Chayan Dutta
- Department of Chemistry , Rice University , Houston , Texas 77005 , United States
| | - Vasanthi Jayaraman
- Department of Biochemistry and Molecular Biology , University of Texas Health Medical School , Houston , Texas 77005 , United States
| | - Christy F Landes
- Department of Chemistry , Rice University , Houston , Texas 77005 , United States.,Department of Electrical and Computer Engineering , Rice University , Houston , Texas 77005 , United States
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6
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Tamiya Y, Watanabe R, Noji H, Li CB, Komatsuzaki T. Effects of non-equilibrium angle fluctuation on F 1-ATPase kinetics induced by temperature increase. Phys Chem Chem Phys 2018; 20:1872-1880. [PMID: 29292807 DOI: 10.1039/c7cp06256g] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
F1-ATPase (F1) is an efficient rotary protein motor, whose reactivity is modulated by the rotary angle to utilize thermal fluctuation. In order to elucidate how its kinetics are affected by the change in the fluctuation, we have extended the reaction-diffusion formalism [R. Watanabe et al., Biophys. J., 2013, 105, 2385] applicable to a wider range of temperatures based on experimental data analysis of F1 derived from thermophilic Bacillus under high ATP concentration conditions. Our simulation shows that the rotary angle distribution manifests a stronger non-equilibrium feature as the temperature increases, because ATP hydrolysis and Pi release are more accelerated compared with the timescale of rotary angle relaxation. This effect causes the rate coefficient obtained from dwell time fitting to deviate from the Arrhenius relation in Pi release, which has been assumed in the previous activation thermodynamic quantities estimation using linear Arrhenius fitting. Larger negative correlation is also found between hydrolysis and Pi release waiting time in a catalytic dwell with the increase in temperature. This loss of independence between the two successive reactions at the catalytic dwell sheds doubt on the conventional dwell time fitting to obtain rate coefficients with a double exponential function at temperatures higher than 65 °C, which is close to the physiological temperature of the thermophilic Bacillus.
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Affiliation(s)
- Yuji Tamiya
- Department of Mathematics, Hokkaido University, Sapporo 001-0020, Japan
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7
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Taylor JN, Pirchi M, Haran G, Komatsuzaki T. Deciphering hierarchical features in the energy landscape of adenylate kinase folding/unfolding. J Chem Phys 2018; 148:123325. [DOI: 10.1063/1.5016487] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- J. Nicholas Taylor
- Research Institute for Electronic Science, Hokkaido University, Kita 20 Nishi 10, Kita-Ku, Sapporo 001-0020, Japan
| | | | - Gilad Haran
- Weizmann Institute of Science, Rehovot 76100, Israel
| | - Tamiki Komatsuzaki
- Research Institute for Electronic Science, Hokkaido University, Kita 20 Nishi 10, Kita-Ku, Sapporo 001-0020, Japan
- Graduate School of Life Science, Hokkaido University, Sapporo 001-0020, Japan
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8
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Tavakoli M, Taylor JN, Li CB, Komatsuzaki T, Pressé S. Single Molecule Data Analysis: An Introduction. ADVANCES IN CHEMICAL PHYSICS 2017. [DOI: 10.1002/9781119324560.ch4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Meysam Tavakoli
- Physics Department; Indiana University-Purdue University Indianapolis; Indianapolis IN 46202 USA
| | - J. Nicholas Taylor
- Research Institute for Electronic Science; Hokkaido University; Kita 20 Nishi 10 Kita-Ku Sapporo 001-0020 Japan
| | - Chun-Biu Li
- Research Institute for Electronic Science; Hokkaido University; Kita 20 Nishi 10 Kita-Ku Sapporo 001-0020 Japan
- Department of Mathematics; Stockholm University; 106 91 Stockholm Sweden
| | - Tamiki Komatsuzaki
- Research Institute for Electronic Science; Hokkaido University; Kita 20 Nishi 10 Kita-Ku Sapporo 001-0020 Japan
| | - Steve Pressé
- Physics Department; Indiana University-Purdue University Indianapolis; Indianapolis IN 46202 USA
- Department of Chemistry and Chemical Biology; Indiana University-Purdue University Indianapolis; Indianapolis IN 46202 USA
- Department of Cell and Integrative Physiology; Indiana University School of Medicine; Indianapolis IN 46202 USA
- Department of Physics and School of Molecular Sciences; Arizona State University; Tempe AZ 85287 USA
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9
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Chen J, Pyle JR, Sy Piecco KW, Kolomeisky AB, Landes CF. A Two-Step Method for smFRET Data Analysis. J Phys Chem B 2016; 120:7128-32. [DOI: 10.1021/acs.jpcb.6b05697] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Jixin Chen
- Department
of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, United States
| | - Joseph R. Pyle
- Department
of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, United States
| | - Kurt Waldo Sy Piecco
- Department
of Chemistry and Biochemistry, Ohio University, Athens, Ohio 45701, United States
| | | | - Christy F. Landes
- Department
of Chemistry, Rice University, Houston, Texas 77251, United States
- Department
of Electrical and Computer Engineering, Rice University, Houston, Texas 77251, United States
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10
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Koorehdavoudi H, Bogdan P. A Statistical Physics Characterization of the Complex Systems Dynamics: Quantifying Complexity from Spatio-Temporal Interactions. Sci Rep 2016; 6:27602. [PMID: 27297496 PMCID: PMC4906350 DOI: 10.1038/srep27602] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 05/20/2016] [Indexed: 12/28/2022] Open
Abstract
Biological systems are frequently categorized as complex systems due to their capabilities of generating spatio-temporal structures from apparent random decisions. In spite of research on analyzing biological systems, we lack a quantifiable framework for measuring their complexity. To fill this gap, in this paper, we develop a new paradigm to study a collective group of N agents moving and interacting in a three-dimensional space. Our paradigm helps to identify the spatio-temporal states of the motion of the group and their associated transition probabilities. This framework enables the estimation of the free energy landscape corresponding to the identified states. Based on the energy landscape, we quantify missing information, emergence, self-organization and complexity for a collective motion. We show that the collective motion of the group of agents evolves to reach the most probable state with relatively lowest energy level and lowest missing information compared to other possible states. Our analysis demonstrates that the natural group of animals exhibit a higher degree of emergence, self-organization and complexity over time. Consequently, this algorithm can be integrated into new frameworks to engineer collective motions to achieve certain degrees of emergence, self-organization and complexity.
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Affiliation(s)
- Hana Koorehdavoudi
- Department of Aerospace and Mechanical Engineering, University of Southern California, Los Angeles, CA 90089-1453, USA
| | - Paul Bogdan
- Department of Electrical Engineering, University of Southern California, Los Angeles, CA 90089-2560, USA
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11
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Nagahata Y, Maeda S, Teramoto H, Horiyama T, Taketsugu T, Komatsuzaki T. Deciphering Time Scale Hierarchy in Reaction Networks. J Phys Chem B 2015; 120:1961-71. [DOI: 10.1021/acs.jpcb.5b09941] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yutaka Nagahata
- Graduate
School of Life Science, Hokkaido University, Kita 10, Nishi 8, Kita-ku, Sapporo 060-0812, Japan
| | - Satoshi Maeda
- Department
of Chemistry, Faculty of Science, Hokkaido University, Kita 10,
Nishi 8, Kita-ku, Sapporo 060-0810, Japan
| | - Hiroshi Teramoto
- Graduate
School of Life Science, Hokkaido University, Kita 10, Nishi 8, Kita-ku, Sapporo 060-0812, Japan
- Molecule
and Life Nonlinear Sciences Laboratory, Research Institute for Electronic
Science, Hokkaido University, Kita 20, Nishi 10, Kita-ku, Sapporo 001-0020, Japan
| | - Takashi Horiyama
- Graduate
School of Science and Engineering, Saitama University, Shimo-Ookubo
255, Sakura-ku, Saitama 338-8570, Japan
| | - Tetsuya Taketsugu
- Department
of Chemistry, Faculty of Science, Hokkaido University, Kita 10,
Nishi 8, Kita-ku, Sapporo 060-0810, Japan
| | - Tamiki Komatsuzaki
- Graduate
School of Life Science, Hokkaido University, Kita 10, Nishi 8, Kita-ku, Sapporo 060-0812, Japan
- Molecule
and Life Nonlinear Sciences Laboratory, Research Institute for Electronic
Science, Hokkaido University, Kita 20, Nishi 10, Kita-ku, Sapporo 001-0020, Japan
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12
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ATP hydrolysis assists phosphate release and promotes reaction ordering in F1-ATPase. Nat Commun 2015; 6:10223. [PMID: 26678797 PMCID: PMC4703894 DOI: 10.1038/ncomms10223] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Accepted: 11/16/2015] [Indexed: 12/28/2022] Open
Abstract
F1-ATPase (F1) is a rotary motor protein that can efficiently convert chemical energy to mechanical work of rotation via fine coordination of its conformational motions and reaction sequences. Compared with reactant binding and product release, the ATP hydrolysis has relatively little contributions to the torque and chemical energy generation. To scrutinize possible roles of ATP hydrolysis, we investigate the detailed statistics of the catalytic dwells from high-speed single wild-type F1 observations. Here we report a small rotation during the catalytic dwell triggered by the ATP hydrolysis that is indiscernible in previous studies. Moreover, we find in freely rotating F1 that ATP hydrolysis is followed by the release of inorganic phosphate with low synthesis rates. Finally, we propose functional roles of the ATP hydrolysis as a key to kinetically unlock the subsequent phosphate release and promote the correct reaction ordering.
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13
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Where the complex things are: single molecule and ensemble spectroscopic investigations of protein folding dynamics. Curr Opin Struct Biol 2015; 36:1-9. [PMID: 26687767 DOI: 10.1016/j.sbi.2015.11.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Accepted: 11/10/2015] [Indexed: 01/11/2023]
Abstract
Progress in our understanding of the simple folding dynamics of small proteins and the complex dynamics of large proteins is reviewed. Recent characterizations of the folding transition path of small proteins revealed a simple dynamics explainable by the native centric model. In contrast, the accumulated data showed the substates containing residual structures in the unfolded state and partially populated intermediates, causing complexity in the early folding dynamics of small proteins. The size of the unfolded proteins in the absence of denaturants is likely expanded but still controversial. The steady progress in the observation of folding of large proteins has clarified the rapid formation of long-range contacts that seem inconsistent with the native centric model, suggesting that the folding strategy of large proteins is distinct from that of small proteins.
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