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Parkin D, Takano M. Coulombic Organization in Membrane-Embedded Rotary Motor of ATP Synthase. J Phys Chem B 2023; 127:1552-1562. [PMID: 36734508 DOI: 10.1021/acs.jpcb.2c07875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The electrochemical potential difference of protons across the membrane is used to synthesize ATP through the proton-motive rotatory motion of the membrane-embedded region of ATP synthase called Fo. In this study, we illuminate the unsolved proton-motive rotary mechanism of Fo on the basis of atomistic simulation with full description of protein, lipid, and water molecules, and highlight the underlying Coulombic design. We first show that a water channel is spontaneously formed at the interfacial region between the rotor (c-ring) and the stator (a-subunit). The observed water channel is a full channel penetrating the membrane, but a Coulomb barrier by a strictly conserved arginine of the a-subunit dominates at the midpoint of the full channel, preventing proton leakage. Our molecular dynamics simulation further demonstrates that the Coulomb attraction between the arginine and the essential glutamic acid of the c-subunit drives the c-ring rotation. We finally illustrate that the charge-state changes of the glutamic acids, enabled by the electrochemical potential difference of proton and the thermal motion, can produce unidirectional rotation of the c-ring.
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Affiliation(s)
- Dan Parkin
- Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-Ku, Tokyo169-8555, Japan
| | - Mitsunori Takano
- Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-Ku, Tokyo169-8555, Japan.,Department of Pure and Applied Physics, Waseda University, 3-8-1 Okubo, Shinjuku-Ku, Tokyo169-8555, Japan
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Abstract
Considerable electric fields are present within living cells, and the role of bioelectricity has been well established at the organismal level. Yet much remains to be learned about electric-field effects on protein function. Here, we use phototriggered charge injection from a site-specifically attached ruthenium photosensitizer to directly demonstrate the effect of dynamic charge redistribution within a protein. We find that binding of an antibody to phosphoglycerate kinase (PGK) is increased twofold under illumination. Remarkably, illumination is found to suppress the enzymatic activity of PGK by a factor as large as three. These responses are sensitive to the photosensitizer position on the protein. Surprisingly, left (but not right) circularly polarized light elicits these responses, indicating that the electrons involved in the observed dynamics are spin polarized, due to spin filtration by protein chiral structures. Our results directly establish the contribution of electrical polarization as an allosteric signal within proteins. Future experiments with phototriggered charge injection will allow delineation of charge rearrangement pathways within proteins and will further depict their effects on protein function.
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Timsit Y, Grégoire SP. Towards the Idea of Molecular Brains. Int J Mol Sci 2021; 22:ijms222111868. [PMID: 34769300 PMCID: PMC8584932 DOI: 10.3390/ijms222111868] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/24/2021] [Accepted: 10/28/2021] [Indexed: 02/06/2023] Open
Abstract
How can single cells without nervous systems perform complex behaviours such as habituation, associative learning and decision making, which are considered the hallmark of animals with a brain? Are there molecular systems that underlie cognitive properties equivalent to those of the brain? This review follows the development of the idea of molecular brains from Darwin’s “root brain hypothesis”, through bacterial chemotaxis, to the recent discovery of neuron-like r-protein networks in the ribosome. By combining a structural biology view with a Bayesian brain approach, this review explores the evolutionary labyrinth of information processing systems across scales. Ribosomal protein networks open a window into what were probably the earliest signalling systems to emerge before the radiation of the three kingdoms. While ribosomal networks are characterised by long-lasting interactions between their protein nodes, cell signalling networks are essentially based on transient interactions. As a corollary, while signals propagated in persistent networks may be ephemeral, networks whose interactions are transient constrain signals diffusing into the cytoplasm to be durable in time, such as post-translational modifications of proteins or second messenger synthesis. The duration and nature of the signals, in turn, implies different mechanisms for the integration of multiple signals and decision making. Evolution then reinvented networks with persistent interactions with the development of nervous systems in metazoans. Ribosomal protein networks and simple nervous systems display architectural and functional analogies whose comparison could suggest scale invariance in information processing. At the molecular level, the significant complexification of eukaryotic ribosomal protein networks is associated with a burst in the acquisition of new conserved aromatic amino acids. Knowing that aromatic residues play a critical role in allosteric receptors and channels, this observation suggests a general role of π systems and their interactions with charged amino acids in multiple signal integration and information processing. We think that these findings may provide the molecular basis for designing future computers with organic processors.
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Affiliation(s)
- Youri Timsit
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO UM110, 13288 Marseille, France
- Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara GOSEE, 3 rue Michel-Ange, 75016 Paris, France
- Correspondence:
| | - Sergeant-Perthuis Grégoire
- Institut de Mathématiques de Jussieu—Paris Rive Gauche (IMJ-PRG), UMR 7586, CNRS-Université Paris Diderot, 75013 Paris, France;
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Ghosh S, Banerjee-Ghosh K, Levy D, Riven I, Naaman R, Haran G. Substrates Modulate Charge-Reorganization Allosteric Effects in Protein-Protein Association. J Phys Chem Lett 2021; 12:2805-2808. [PMID: 33710900 PMCID: PMC8041378 DOI: 10.1021/acs.jpclett.1c00437] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Protein function may be modulated by an event occurring far away from the functional site, a phenomenon termed allostery. While classically allostery involves conformational changes, we recently observed that charge redistribution within an antibody can also lead to an allosteric effect, modulating the kinetics of binding to target antigen. In the present work, we study the association of a polyhistidine tagged enzyme (phosphoglycerate kinase, PGK) to surface-immobilized anti-His antibodies, finding a significant Charge-Reorganization Allostery (CRA) effect. We further observe that PGK's negatively charged nucleotide substrates modulate CRA substantially, even though they bind far away from the His-tag-antibody interaction interface. In particular, binding of ATP reduces CRA by more than 50%. The results indicate that CRA is affected by the binding of charged molecules to a protein and provide further insight into the significant role that charge redistribution can play in protein function.
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Sato H, Sugishima M, Tsukaguchi M, Masuko T, Iijima M, Takano M, Omata Y, Hirabayashi K, Wada K, Hisaeda Y, Yamamoto K. Crystal structures of hydroxymethylbilane synthase complexed with a substrate analog: a single substrate-binding site for four consecutive condensation steps. Biochem J 2021; 478:1023-1042. [PMID: 33600566 PMCID: PMC7959689 DOI: 10.1042/bcj20200996] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/10/2021] [Accepted: 02/12/2021] [Indexed: 11/30/2022]
Abstract
Hydroxymethylbilane synthase (HMBS), which is involved in the heme biosynthesis pathway, has a dipyrromethane cofactor and combines four porphobilinogen (PBG) molecules to form a linear tetrapyrrole, hydroxymethylbilane. Enzyme kinetic study of human HMBS using a PBG-derivative, 2-iodoporphobilinogen (2-I-PBG), exhibited noncompetitive inhibition with the inhibition constant being 5.4 ± 0.3 µM. To elucidate the reaction mechanism of HMBS in detail, crystal structure analysis of 2-I-PBG-bound holo-HMBS and its reaction intermediate possessing two PBG molecules (ES2), and inhibitor-free ES2 was performed at 2.40, 2.31, and 1.79 Å resolution, respectively. Their overall structures are similar to that of inhibitor-free holo-HMBS, and the differences are limited near the active site. In both 2-I-PBG-bound structures, 2-I-PBG is located near the terminus of the cofactor or the tetrapyrrole chain. The propionate group of 2-I-PBG interacts with the side chain of Arg173, and its acetate group is associated with the side chains of Arg26 and Ser28. Furthermore, the aminomethyl group and pyrrole nitrogen of 2-I-PBG form hydrogen bonds with the side chains of Gln34 and Asp99, respectively. These amino acid residues form a single substrate-binding site, where each of the four PBG molecules covalently binds to the cofactor (or oligopyrrole chain) consecutively, ultimately forming a hexapyrrole chain. Molecular dynamics simulation of the ES2 intermediate suggested that the thermal fluctuation of the lid and cofactor-binding loops causes substrate recruitment and oligopyrrole chain shift needed for consecutive condensation. Finally, the hexapyrrole chain is hydrolyzed self-catalytically to produce hydroxymethylbilane.
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Affiliation(s)
- Hideaki Sato
- Department of Medical Biochemistry, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan
| | - Masakazu Sugishima
- Department of Medical Biochemistry, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan
| | - Mai Tsukaguchi
- Department of Medical Biochemistry, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan
| | - Takahiro Masuko
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Mikuru Iijima
- Department of Pure and Applied Physics, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Mitsunori Takano
- Department of Pure and Applied Physics, School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan
| | - Yoshiaki Omata
- Department of Molecular Biology, Faculty of Pharmaceutical Science, Yokohama University of Pharmacy, 601 Matano-cho, Totsuka-ku, Yokohama 245-0066, Japan
| | - Kei Hirabayashi
- Department of Applied Chemistry, Faculty of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan
| | - Kei Wada
- Department of Medical Sciences, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki 889-1692, Japan
| | - Yoshio Hisaeda
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Ken Yamamoto
- Department of Medical Biochemistry, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan
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Biased Brownian Motion of KIF1A and the Role of Tubulin's C-Terminal Tail Studied by Molecular Dynamics Simulation. Int J Mol Sci 2021; 22:ijms22041547. [PMID: 33557020 PMCID: PMC7913626 DOI: 10.3390/ijms22041547] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 01/28/2021] [Accepted: 02/01/2021] [Indexed: 12/29/2022] Open
Abstract
KIF1A is a kinesin family protein that moves over a long distance along the microtubule (MT) to transport synaptic vesicle precursors in neurons. A single KIF1A molecule can move toward the plus-end of MT in the monomeric form, exhibiting the characteristics of biased Brownian motion. However, how the bias is generated in the Brownian motion of KIF1A has not yet been firmly established. To elucidate this, we conducted a set of molecular dynamics simulations and observed the binding of KIF1A to MT. We found that KIF1A exhibits biased Brownian motion along MT as it binds to MT. Furthermore, we show that the bias toward the plus-end is generated by the ratchet-like energy landscape for the KIF1A-MT interaction, in which the electrostatic interaction and the negatively-charged C-terminal tail (CTT) of tubulin play an essential role. The relevance to the post-translational modifications of CTT is also discussed.
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Okami M, Sunada Y, Hatori K. Lysozyme-induced suppression of enzymatic and motile activities of actin-myosin: Impact of basic proteins. Int J Biol Macromol 2020; 163:1147-1153. [PMID: 32668307 DOI: 10.1016/j.ijbiomac.2020.07.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 07/06/2020] [Accepted: 07/06/2020] [Indexed: 10/23/2022]
Abstract
Electrostatic interactions between actin filaments and myosin molecules, which are ubiquitous proteins in eukaryotes, are crucial for their enzymatic activity and motility. Nonspecific electrostatic interactions between proteins are unavoidable in cells; therefore, it is worth exploring how ambient proteins, such as polyelectrolytes, affect actin-myosin functions. To understand the effect of counterionic proteins on actin-myosin, we examined ATPase activity and sliding velocity via actin-myosin interactions in the presence of the basic model protein hen egg lysozyme. In an in vitro motility assay with ATP, the sliding velocity of actin filaments on heavy meromyosin (HMM) decreased with increasing lysozyme concentrations. Actin filaments were completely stalled at a lysozyme concentration above 0.08 mg/mL. Lysozyme decreased the ATP hydrolysis rate of the actin-HMM complex but not that HMM alone. Co-sedimentation assays revealed that lysozyme enhanced the binding of HMM to actin filaments in the presence of ATP. Additionally, lysozyme could bind to actin and myosin filaments. The inhibitory effect of poly-l-lysine, histone mixture, and lactoferrin on the motility of actin-myosin was higher than that of lysozyme. Thus, nonspecific electrostatic interactions of basic proteins are involved in the bundling of actin filaments and modulation of essential functions of the actomyosin complex.
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Affiliation(s)
- Masaki Okami
- Department of Bio-Systems Engineering, Graduate School of Science and Engineering, Yamagata University, 4-3-16, Jyonan, Yonezawa, Yamagata 992-8510, Japan
| | - Yuma Sunada
- Department of Bio-Systems Engineering, Graduate School of Science and Engineering, Yamagata University, 4-3-16, Jyonan, Yonezawa, Yamagata 992-8510, Japan
| | - Kuniyuki Hatori
- Department of Bio-Systems Engineering, Graduate School of Science and Engineering, Yamagata University, 4-3-16, Jyonan, Yonezawa, Yamagata 992-8510, Japan.
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Coupling of Redox and Structural States in Cytochrome P450 Reductase Studied by Molecular Dynamics Simulation. Sci Rep 2019; 9:9341. [PMID: 31249341 PMCID: PMC6597723 DOI: 10.1038/s41598-019-45690-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 06/10/2019] [Indexed: 01/09/2023] Open
Abstract
Cytochrome P450 reductase (CPR) is the key protein that regulates the electron transfer from NADPH to various heme-containing monooxygenases. CPR has two flavin-containing domains: one with flavin adenine dinucleotide (FAD), called FAD domain, and the other with flavin mononucleotide (FMN), called FMN domain. It is considered that the electron transfer occurs via FAD and FMN (NADPH → FAD → FMN → monooxygenase) and is regulated by an interdomain open-close motion. It is generally thought that the structural state is coupled with the redox state, which, however, has not yet been firmly established. In this report, we studied the coupling of the redox and the structural states by full-scale molecular dynamics (MD) simulation of CPR (total 86.4 μs). Our MD result showed that while CPR predominantly adopts the closed state both in the oxidized and reduced states, it exhibits a tendency to open in the reduced state. We also found a correlation between the FAD-FMN distance and the predicted FMN-monooxygenase distance, which is embedded in the equilibrium thermal fluctuation of CPR. Based on these results, a physical mechanism for the electron transfer by CPR is discussed.
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