1
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Kuttenlochner W, Beller P, Kaysser L, Groll M. Deciphering the SAM- and Metal-Dependent Mechanism of O-Methyltransferases in Cystargolide and Belactosin Biosynthesis: A Structure-Activity Relationship Study. J Biol Chem 2024:107646. [PMID: 39121999 DOI: 10.1016/j.jbc.2024.107646] [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: 05/21/2024] [Revised: 07/18/2024] [Accepted: 07/25/2024] [Indexed: 08/12/2024] Open
Abstract
Cystargolides and belactosins are natural products with a distinct dipeptide structure and an electrophilic β-lactone warhead. They are known to inhibit proteases such as the proteasome or caseinolytic protease P, highlighting their potential in treating cancers and neurodegenerative diseases. Recent genetic analyses have shown homology between the biosynthetic pathways of the two inhibitors. Here, we characterize the O-methyltransferases BelI and CysG, which catalyze the initial step of β-lactone formation. Employing techniques such as crystallography, computational analysis, mutagenesis, and activity assays, we identified a His-His-Asp (HHD) motif in the active sites of the two enzymes, which is crucial for binding a catalytically active calcium ion. Our findings thus elucidate a conserved divalent metal-dependent mechanism in both biosynthetic pathways that distinguishes BelI and CysG from previously characterized O-methyltransferases.
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Affiliation(s)
- Wolfgang Kuttenlochner
- Department of Bioscience, Center for Protein Assemblies (CPA), TUM School of Natural Sciences, Technical University of Munich, Garching, Germany.
| | - Patrick Beller
- Department of Pharmaceutical Biology, Pharmaceutical Institute, University of Tübingen, Tübingen, Germany
| | - Leonard Kaysser
- Department of Pharmaceutical Biology, Institute for Drug Discovery, University of Leipzig, Leipzig, Germany
| | - Michael Groll
- Department of Bioscience, Center for Protein Assemblies (CPA), TUM School of Natural Sciences, Technical University of Munich, Garching, Germany.
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2
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Zhang P, Nde J, Eliaz Y, Jennings N, Cieplak P, Cheung MS. Chemistry-informed Machine Learning Explains Calcium-binding Proteins' Fuzzy Shape for Communicating Changes in the Atomic States of Calcium Ions. ARXIV 2024:arXiv:2407.17017v1. [PMID: 39108291 PMCID: PMC11302678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
Proteins' fuzziness are features for communicating changes in cell signaling instigated by binding with secondary messengers, such as calcium ions, associated with the coordination of muscle contraction, neurotransmitter release, and gene expression. Binding with the disordered parts of a protein, calcium ions must balance their charge states with the shape of calcium-binding proteins and their versatile pool of partners depending on the circumstances they transmit, but it is unclear whether the limited experimental data available can be used to train models to accurately predict the charges of calcium-binding protein variants. Here, we developed a chemistry-informed, machine-learning algorithm that implements a game theoretic approach to explain the output of a machine-learning model without the prerequisite of an excessively large database for high-performance prediction of atomic charges. We used the ab initio electronic structure data representing calcium ions and the structures of the disordered segments of calcium-binding peptides with surrounding water molecules to train several explainable models. Network theory was used to extract the topological features of atomic interactions in the structurally complex data dictated by the coordination chemistry of a calcium ion, a potent indicator of its charge state in protein. With our designs, we provided a framework of explainable machine learning model to annotate atomic charges of calcium ions in calcium-binding proteins with domain knowledge in response to the chemical changes in an environment based on the limited size of scientific data in a genome space.
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Affiliation(s)
- Pengzhi Zhang
- Center for Bioinformatics and Computational Biology, Houston Methodist Research Institute, Houston, TX, USA
| | - Jules Nde
- Department of Physics, University of Washington, Seattle, WA, USA
| | - Yossi Eliaz
- Department of Physics, University of Houston, Houston, TX, USA
- Computer Science Department, HIT Holon Institute of Technology, Holon, Israel
| | | | - Piotr Cieplak
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Margaret S Cheung
- Department of Physics, University of Washington, Seattle, WA, USA
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA
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3
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An J, Wang Y, Li W, Liu W, Zeng X, Liu G, Liu X, Li H. Evaluating the capability of soybean peptides as calcium ion carriers: a study through sequence analysis and molecular dynamics simulations. RSC Adv 2024; 14:15542-15553. [PMID: 38741956 PMCID: PMC11089645 DOI: 10.1039/d4ra02916j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Accepted: 05/06/2024] [Indexed: 05/16/2024] Open
Abstract
Calcium homeostasis imbalance in the body can lead to a variety of chronic diseases. Supplement efficiency is essential. Peptide calcium chelate, a fourth-generation calcium supplement, offers easy absorption and minimal side effects. Its effectiveness relies on peptide's calcium binding capacity. However, research on amino acid sequences in peptides with high calcium binding capacity (HCBC) is limited, affecting the efficient identification of such peptides. This study used soybean peptides (SP), separated and purified by gel chromatography, to obtain HCBC peptide (137.45 μg mg-1) and normal peptide (≤95.78 μg mg-1). Mass spectrometry identified the sequences of these peptides, and an analysis of the positional distribution of characteristic amino acids followed. Two HCBC peptides with sequences GGDLVS (271.55 μg mg-1) and YEGVIL (272.54 μg mg-1) were discovered. Molecular dynamics showed that when either aspartic acid is located near the N-terminal's middle, or glutamic acid is near the end, or in cases of continuous Asp or Glu, the binding speed, probability, and strength between the peptide and calcium ions are superior compared to those at other locations. The study's goal was to clarify how the positions of characteristic amino acids in peptides affect calcium binding, aiding in developing peptide calcium chelates as a novel calcium supplement.
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Affiliation(s)
- Jiulong An
- Key Laboratory of Geriatric Nutrition and Health (Beijing Technology and Business University), Ministry of Education Beijing 100048 China
| | - Yumei Wang
- Key Laboratory of Geriatric Nutrition and Health (Beijing Technology and Business University), Ministry of Education Beijing 100048 China
| | - Wenhui Li
- Key Laboratory of Geriatric Nutrition and Health (Beijing Technology and Business University), Ministry of Education Beijing 100048 China
| | - Wanlu Liu
- Key Laboratory of Geriatric Nutrition and Health (Beijing Technology and Business University), Ministry of Education Beijing 100048 China
| | - Xiangquan Zeng
- Key Laboratory of Geriatric Nutrition and Health (Beijing Technology and Business University), Ministry of Education Beijing 100048 China
- Key Laboratory of Green and Low-carbon Processing Technology for Plant-based Food of China National Light Industry Council, Beijing Technology and Business University Beijing 100048 China
| | - Guoqi Liu
- Key Laboratory of Green and Low-carbon Processing Technology for Plant-based Food of China National Light Industry Council, Beijing Technology and Business University Beijing 100048 China
| | - Xinqi Liu
- Key Laboratory of Geriatric Nutrition and Health (Beijing Technology and Business University), Ministry of Education Beijing 100048 China
| | - He Li
- Key Laboratory of Geriatric Nutrition and Health (Beijing Technology and Business University), Ministry of Education Beijing 100048 China
- Key Laboratory of Green and Low-carbon Processing Technology for Plant-based Food of China National Light Industry Council, Beijing Technology and Business University Beijing 100048 China
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4
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Ponnusamy T, Velusamy P, Shanmughapriya S. Mrs2-mediated mitochondrial magnesium uptake is essential for the regulation of MCU-mediated mitochondrial Ca 2+ uptake and viability. Mitochondrion 2024; 76:101877. [PMID: 38599304 DOI: 10.1016/j.mito.2024.101877] [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: 12/27/2023] [Revised: 03/07/2024] [Accepted: 04/07/2024] [Indexed: 04/12/2024]
Abstract
Mitochondrial Ca2+ uptake is essential in regulating bioenergetics, cell death, and cytosolic Ca2+ transients. Mitochondrial Calcium Uniporter (MCU) mediates the mitochondrial Ca2+ uptake. Though MCU regulation by MICUs is unequivocally established, there needs to be more knowledge of whether divalent cations regulate MCU. Here, we set out to understand the mitochondrial matrix Mg2+-dependent regulation of MCU activity. We showed that decreased matrix [Mg2+] is associated with increased MCU activity and significantly prompted mitochondrial permeability transition pore opening. Our findings support the critical role of mMg2+ in regulating MCU activity.
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Affiliation(s)
- Thiruvelselvan Ponnusamy
- Heart and Vascular Institute, Department of Medicine, Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Prema Velusamy
- Heart and Vascular Institute, Department of Medicine, Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Santhanam Shanmughapriya
- Heart and Vascular Institute, Department of Medicine, Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA.
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5
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Nietmann P, Kaub K, Suchenko A, Stenz S, Warnecke C, Balasubramanian MK, Janshoff A. Cytosolic actin isoforms form networks with different rheological properties that indicate specific biological function. Nat Commun 2023; 14:7989. [PMID: 38042893 PMCID: PMC10693642 DOI: 10.1038/s41467-023-43653-w] [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: 05/03/2023] [Accepted: 11/15/2023] [Indexed: 12/04/2023] Open
Abstract
The implications of the existence of different actins expressed in epithelial cells for network mechanics and dynamics is investigated by microrheology and confocal imaging. γ-actin predominately found in the apical cortex forms stiffer networks compared to β-actin, which is preferentially organized in stress fibers. We attribute this to selective interactions with Mg2+-ions interconnecting the filaments' N-termini. Bundling propensity of the isoforms is different in the presence of Mg2+-ions, while crosslinkers such as α-actinin, fascin, and heavy meromyosin alter the mechanical response independent of the isoform. In the presence of myosin, β-actin networks show a large number of small contraction foci, while γ-actin displays larger but fewer foci indicative of a stronger interaction with myosin motors. We infer that subtle changes in the amino acid sequence of actin isoforms lead to alterations of the mechanical properties on the network level with potential implications for specific biological functions.
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Affiliation(s)
- Peter Nietmann
- Institute of Physical Chemistry, University of Goettingen, Tammannstr. 6, Göttingen, 37077, Germany
| | - Kevin Kaub
- Institute of Physical Chemistry, University of Goettingen, Tammannstr. 6, Göttingen, 37077, Germany
- Max Planck School Matter to Life, Max Planck Institute for Medical Research, Jahnstr. 29, Heidelberg, 69120, Germany
| | - Andrejus Suchenko
- Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK
| | - Susanne Stenz
- Institute of Physical Chemistry, University of Goettingen, Tammannstr. 6, Göttingen, 37077, Germany
| | - Claas Warnecke
- Institute of Physical Chemistry, University of Goettingen, Tammannstr. 6, Göttingen, 37077, Germany
| | | | - Andreas Janshoff
- Institute of Physical Chemistry, University of Goettingen, Tammannstr. 6, Göttingen, 37077, Germany.
- Max Planck School Matter to Life, Max Planck Institute for Medical Research, Jahnstr. 29, Heidelberg, 69120, Germany.
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6
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Warren ID, Knowles AJ. Social Experience during Adolescence Shapes Maturation of Parvalbumin-Positive Interneurons in the Left Orbitofrontal Cortex. J Neurosci 2023; 43:6109-6111. [PMID: 37648447 PMCID: PMC10476634 DOI: 10.1523/jneurosci.0792-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 07/18/2023] [Accepted: 07/20/2023] [Indexed: 09/01/2023] Open
Affiliation(s)
- Ian D Warren
- Department of Psychology, University of Tennessee, Knoxville, Knoxville, Tennessee 37996
| | - Asante J Knowles
- Department of Psychology, University of Tennessee, Knoxville, Knoxville, Tennessee 37996
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7
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Neamtu A, Serban DN, Barritt GJ, Isac DL, Vasiliu T, Laaksonen A, Serban IL. Molecular dynamics simulations reveal the hidden EF-hand of EF-SAM as a possible key thermal sensor for STIM1 activation by temperature. J Biol Chem 2023; 299:104970. [PMID: 37380078 PMCID: PMC10400917 DOI: 10.1016/j.jbc.2023.104970] [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: 02/10/2023] [Revised: 06/07/2023] [Accepted: 06/22/2023] [Indexed: 06/30/2023] Open
Abstract
Intracellular calcium signaling is essential for many cellular processes, including store-operated Ca2+ entry (SOCE), which is initiated by stromal interaction molecule 1 (STIM1) detecting endoplasmic reticulum (ER) Ca2+ depletion. STIM1 is also activated by temperature independent of ER Ca2+ depletion. Here we provide evidence, from advanced molecular dynamics simulations, that EF-SAM may act as a true temperature sensor for STIM1, with the prompt and extended unfolding of the hidden EF-hand subdomain (hEF) even at slightly elevated temperatures, exposing a highly conserved hydrophobic Phe108. Our study also suggests an interplay between Ca2+ and temperature sensing, as both, the canonical EF-hand subdomain (cEF) and the hidden EF-hand subdomain (hEF), exhibit much higher thermal stability in the Ca2+-loaded form compared to the Ca2+-free form. The SAM domain, surprisingly, displays high thermal stability compared to the EF-hands and may act as a stabilizer for the latter. We propose a modular architecture for the EF-hand-SAM domain of STIM1 composed of a thermal sensor (hEF), a Ca2+ sensor (cEF), and a stabilizing domain (SAM). Our findings provide important insights into the mechanism of temperature-dependent regulation of STIM1, which has broad implications for understanding the role of temperature in cellular physiology.
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Affiliation(s)
- Andrei Neamtu
- Department of Physiology, "Grigore T. Popa" University of Medicine and Pharmacy, Iasi, Romania; Center of Advanced Research in Bionanocojugates and Biopolymers, "Petru Poni" Institute of Macromolecular Chemistry Iasi, Iasi, Romania
| | - Dragomir N Serban
- Department of Physiology, "Grigore T. Popa" University of Medicine and Pharmacy, Iasi, Romania.
| | - Greg J Barritt
- Discipline of Medical Biochemistry, College of Medicine and Public Health, Flinders University, Adelaide, SA, Australia
| | - Dragos Lucian Isac
- Center of Advanced Research in Bionanocojugates and Biopolymers, "Petru Poni" Institute of Macromolecular Chemistry Iasi, Iasi, Romania
| | - Tudor Vasiliu
- Center of Advanced Research in Bionanocojugates and Biopolymers, "Petru Poni" Institute of Macromolecular Chemistry Iasi, Iasi, Romania
| | - Aatto Laaksonen
- Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, Sweden; Centre of Advanced Research in Bionanoconjugates and Biopolymers, Petru Poni Institute of Macromolecular Chemistry, Iasi, Romania; State Key Laboratory of Materials-Oriented and Chemical Engineering, Nanjing Tech University, Nanjing, P. R. China
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8
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Ponnusamy T, Velusamy P, Kumar A, Morris D, Zhang X, Ning G, Klinger M, Copper JE, Rajan S, Cheung JY, Natarajaseenivasan K, Mnatsakanyan N, Shanmughapriya S. Mitochondrial Magnesium is the cationic rheostat for MCU-mediated mitochondrial Ca 2+ uptake. RESEARCH SQUARE 2023:rs.3.rs-3088175. [PMID: 37502932 PMCID: PMC10371168 DOI: 10.21203/rs.3.rs-3088175/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Calcium (Ca2+) uptake by mitochondria is essential in regulating bioenergetics, cell death, and cytosolic Ca2+ transients. Mitochondrial Calcium Uniporter (MCU) mediates the mitochondrial Ca2+ uptake. MCU is a heterooligomeric complex with a pore-forming component and accessory proteins required for channel activity. Though MCU regulation by MICUs is unequivocally established, there needs to be more knowledge of whether divalent cations regulate MCU. Here we set out to understand the mitochondrial matrix Mg2+-dependent regulation of MCU activity. We showed Mrs2 as the authentic mammalian mitochondrial Mg2+ channel using the planar lipid bilayer recordings. Using a liver-specific Mrs2 KO mouse model, we showed that decreased matrix [Mg2+] is associated with increased MCU activity and matrix Ca2+ overload. The disruption of Mg2+dependent MCU regulation significantly prompted mitochondrial permeability transition pore opening-mediated cell death during tissue IR injury. Our findings support a critical role for mMg2+ in regulating MCU activity and attenuating mCa2+ overload.
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Affiliation(s)
- Thiruvelselvan Ponnusamy
- Heart and Vascular Institute, Department of Medicine, Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Prema Velusamy
- Heart and Vascular Institute, Department of Medicine, Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Amrendra Kumar
- Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Daniel Morris
- Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Xueqian Zhang
- Cardiovascular Medicine, Department of Medicine, UMass Chan Medical School, Worcester, MA 01655, USA
| | - Gang Ning
- Microscopy Core Facility, Penn State Huck Institutes of the Life Sciences, University Park, PA 16802, USA
| | - Marianne Klinger
- Department of Pathology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Jean E. Copper
- Department of Pathology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Sudarsan Rajan
- Center for Translational Medicine, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Joseph Y Cheung
- Department of Renal Medicine, Brigham & Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | | | - Nelli Mnatsakanyan
- Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
| | - Santhanam Shanmughapriya
- Heart and Vascular Institute, Department of Medicine, Department of Cellular and Molecular Physiology, Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA
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9
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Identification of radiation responsive RBC membrane associated proteins (RMAPs) in whole-body γ-irradiated New Zealand white rabbits. BIOTECHNOLOGY REPORTS (AMSTERDAM, NETHERLANDS) 2023; 37:e00783. [PMID: 36718137 PMCID: PMC9883204 DOI: 10.1016/j.btre.2023.e00783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/27/2022] [Accepted: 01/14/2023] [Indexed: 01/19/2023]
Abstract
This study is aimed to identify radiation-responsive RBC Membrane Associated Proteins (RMAPs) in Rabbits in vivo. Male New Zealand White rabbits were exposed to a single acute total body γ-radiation dose of 2 Gy at a dose rate of 0.746 Gy/min. Following this, at early time points of 6 h till the 7 d, RMAPs were collected and analyzed by MALDI-TOF-MS. Bioinformatics analysis was conducted to explore the biological functions of these proteins. Based on fold change, radiation responsiveness, GO, pathway enrichment, and hub position in the PPI network, we identified seven RMAPs as potential biomarker candidates viz., PVALB, PRKCB, GPD1, CP2G1, CSNK2B, ATP1B1, TPI1. As per KEGG enrichment, most of the proteins were implicated in cellular radiation response, oxidative damage, DNA repair, apoptosis, immune response, and cell signaling. This study forms the foundation for RMAPs-based Proteomic strategies for high throughput radiation bio-dosimetry for triage in the case of a radiological/nuclear incident.
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10
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Hu H, Quintana J, Weissleder R, Parangi S, Miller M. Deciphering albumin-directed drug delivery by imaging. Adv Drug Deliv Rev 2022; 185:114237. [PMID: 35364124 DOI: 10.1016/j.addr.2022.114237] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 03/10/2022] [Accepted: 03/23/2022] [Indexed: 01/03/2023]
Abstract
Albumin is the most abundant plasma protein, exhibits extended circulating half-life, and its properties have long been exploited for diagnostics and therapies. Many drugs intrinsically bind albumin or have been designed to do so, yet questions remain about true rate limiting factors that govern albumin-based transport and their pharmacological impacts, particularly in advanced solid cancers. Imaging techniques have been central to quantifying - at a molecular and single-cell level - the impact of mechanisms such as phagocytic immune cell signaling, FcRn-mediated recycling, oncogene-driven macropinocytosis, and albumin-drug interactions on spatial albumin deposition and related pharmacology. Macroscopic imaging of albumin-binding probes quantifies vessel structure, permeability, and supports efficiently targeted molecular imaging. Albumin-based imaging in patients and animal disease models thus offers a strategy to understand mechanisms, guide drug development and personalize treatments.
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11
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Wallach C, Klein W, Fässler TF. Nonagermanide Zintl Clusters with Mg2+ Counter Ions. Z Anorg Allg Chem 2022. [DOI: 10.1002/zaac.202200065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | | | - Thomas Friedrich Fässler
- Technische Universität München: Technische Universitat Munchen Department of Chemistry Lichtenbergstr. 4 85747 Garching GERMANY
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12
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Immadisetty K, Sun B, Kekenes-Huskey PM. Structural Changes beyond the EF-Hand Contribute to Apparent Calcium Binding Affinities: Insights from Parvalbumins. J Phys Chem B 2021; 125:6390-6405. [PMID: 34115511 DOI: 10.1021/acs.jpcb.1c01269] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Members of the parvalbumin (PV) family of calcium (Ca2+) binding proteins (CBPs) share a relatively high level of sequence similarity. However, their Ca2+ affinities and selectivities against competing ions like Mg2+ can widely vary. We conducted molecular dynamics simulations of several α-parvalbumin (αPV) constructs with micromolar to nanomolar Ca2+ affinities to identify structural and dynamic features that contribute to their binding of ions. Specifically, we examined a D94S/G98E construct with a lower Ca2+ affinity (≈-18 kcal/mol) relative to the wild type (WT) (≈-22 kcal/mol) and an S55D/E59D variant with enhanced affinity (≈-24 kcal/mol). Additionally, we also examined the binding of Mg2+ to these isoforms, which is much weaker than Ca2+. We used mean spherical approximation (MSA) theory to evaluate ion binding thermodynamics within the proteins' EF-hand domains to account for the impact of ions' finite sizes and the surrounding electrolyte composition. While the MSA scores differentiated Mg2+ from Ca2+, they did not indicate that Ca2+ binding affinities at the binding loop differed between the PV isoforms. Instead, molecular mechanics generalized Born surface area (MM/GBSA) approximation energies, which we used to quantify the thermodynamic cost of structural rearrangement of the proteins upon binding ions, indicated that S55D/E59D αPV favored Ca2+ binding by -20 kcal/mol relative to WT versus 30 kcal/mol for D94S/G98E αPV. Meanwhile, Mg2+ binding was favored for the S55D/E59D αPV and D94S/G98E αPV variants by -18.32 and -1.65 kcal/mol, respectively. These energies implicate significant contributions to ion binding beyond oxygen coordination at the binding loop, which stemmed from changes in α-helicity, β-sheet character, and hydrogen bonding. Hence, Ca2+ affinity and selectivity against Mg2+ are emergent properties stemming from both local effects within the proteins' ion binding sites as well as non-local contributions elsewhere. Our findings broaden our understanding of the molecular bases governing αPV ion binding that are likely shared by members of the broad family of CBPs.
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Affiliation(s)
| | - Bin Sun
- Stritch School of Medicine, Maywood, Illinois 60153, United States
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13
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Ebokaiwe AP, Okori S, Nwankwo JO, Ejike CECC, Osawe SO. Selenium nanoparticles and metformin ameliorate streptozotocin-instigated brain oxidative-inflammatory stress and neurobehavioral alterations in rats. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2021; 394:591-602. [PMID: 33064168 PMCID: PMC7561705 DOI: 10.1007/s00210-020-02000-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 10/11/2020] [Indexed: 12/12/2022]
Abstract
Selenium nanoparticles (SeNPs) are well reported to exhibit pharmacological activities both in vitro and in vivo. However, literature is devoid of studies on the impact of SeNPs and/or metformin (M) against streptozotocin (STZ)-mediated oxidative brain injury and behavioral impairment. Consequently, to fill this gap, diabetes was induced in male Wistar rats by feeding with 10% fructose solution for 2 weeks, followed by a single dose intraperitoneal injection of STZ (40 mg/kg body weight [bwt]). After rats were confirmed diabetic, they were treated orally with 0.1 mg/kg bwt of SeNPs ± M (50 mg/kg bwt), and normal control (NC) received citrate buffer (2 mg/mL) for 5 weeks. In comparison with the diabetic control (DC), SeNPs, and/or M significantly (p < 0.05) lowered blood glucose levels, but increased insulin secretion and pancreatic β-cell function. An increase in locomotor and motor activities evidenced by improved spontaneous alternation, locomotor frequency, hinding, and increased mobility time were observed in treated groups. In addition, there was enhanced brain antioxidant status with a lower acetylcholinesterase (AChE) activity and oxidative-inflammatory stress biomarkers. A significant downregulation of caspase 3 and upregulation of parvalbumin and Nrf2 protein expressions was observed in treated groups. In some of the studied parameters, treated groups were statistically (p < 0.05) insignificant compared with the normal control (NC) group. Overall, co-treatment elicited more efficacy than that of the individual regimen.
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Affiliation(s)
- Azubuike P Ebokaiwe
- Department of Chemistry/Biochemistry and Molecular Biology, Alex Ekwueme Federal University, Ndufu-Alike Ikwo, Abakaliki, Ebonyi State, PMB 1010, Nigeria.
| | - Stephen Okori
- Department of Anatomy, Faculty of Basic Medical Sciences, Cross River University of Technology, Okuku Campus, Okuku, Cross River, Nigeria
| | - Joseph O Nwankwo
- Department of Medical Biochemistry, Alex Ekwueme Federal University, Ndufu-Alike Ikwo, Abakaliki, PMB 1010, Nigeria
| | - Chukwunonso E C C Ejike
- Department of Medical Biochemistry, Alex Ekwueme Federal University, Ndufu-Alike Ikwo, Abakaliki, PMB 1010, Nigeria
| | - Sharon O Osawe
- Department of Biological Sciences, Biochemistry Programme, KolaDaisi University, Ibadan, Oyo State, Nigeria
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14
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Bombardi L, Pedretti M, Conter C, Dominici P, Astegno A. Distinct Calcium Binding and Structural Properties of Two Centrin Isoforms from Toxoplasma gondii. Biomolecules 2020; 10:E1142. [PMID: 32759683 PMCID: PMC7465447 DOI: 10.3390/biom10081142] [Citation(s) in RCA: 5] [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: 06/20/2020] [Revised: 07/27/2020] [Accepted: 07/31/2020] [Indexed: 11/16/2022] Open
Abstract
Centrins are calcium (Ca2+)-binding proteins that have been implicated in several regulatory functions. In the protozoan parasite Toxoplasma gondii, the causative agent of toxoplasmosis, three isoforms of centrin have been identified. While increasing information is now available that links the function of centrins with defined parasite biological processes, knowledge is still limited on the metal-binding and structural properties of these proteins. Herein, using biophysical and structural approaches, we explored the Ca2+ binding abilities and the subsequent effects of Ca2+ on the structure of a conserved (TgCEN1) and a more divergent (TgCEN2) centrin isoform from T. gondii. Our data showed that TgCEN1 and TgCEN2 possess diverse molecular features, suggesting that they play nonredundant roles in parasite physiology. TgCEN1 binds two Ca2+ ions with high/medium affinity, while TgCEN2 binds one Ca2+ with low affinity. TgCEN1 undergoes significant Ca2+-dependent conformational changes that expose hydrophobic patches, supporting a role as a Ca2+ sensor in toxoplasma. In contrast, Ca2+ binding has a subtle influence on conformational features of TgCEN2 without resulting in hydrophobic exposure, suggesting a different Ca2+ relay mode for this isoform. Furthermore, TgCEN1 displays a Ca2+-dependent ability to self-assemble, while TgCEN2 did not. We discuss our findings in the context of Ca2+ signaling in toxoplasma.
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Affiliation(s)
| | | | | | | | - Alessandra Astegno
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy; (L.B.); (M.P.); (C.C.); (P.D.)
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15
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Park D, Yoon HJ, Lee KY, Park SJ, Cheon SH, Lee HH, Lee SJ, Lee BJ. Crystal structure of proteolyzed VapBC and DNA-bound VapBC from Salmonella enterica Typhimurium LT2 and VapC as a putative Ca 2+ -dependent ribonuclease. FASEB J 2020; 34:3051-3068. [PMID: 31908032 DOI: 10.1096/fj.201901989r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 12/13/2019] [Accepted: 12/16/2019] [Indexed: 12/22/2022]
Abstract
Bacterial toxin-antitoxin (TA) system has gained attention for its essential roles in cellular maintenance and survival under harsh environmental conditions such as nutrient deficiency and antibiotic treatment. There are at least 14 TA systems in Salmonella enterica serovar Typhimurium LT2, a pathogenic bacterium, and none of the structures of these TA systems have been determined. We determined the crystal structure of the VapBC TA complex from S. Typhimurium LT2 in proteolyzed and DNA-bound forms at 2.0 Å and 2.8 Å resolution, respectively. The VapC toxin possesses a pilT N-terminal domain (PIN-domain) that shows ribonuclease activity, and the VapB antitoxin has an AbrB-type DNA binding domain. In addition, the structure revealed details of interaction mode between VapBC and the cognate promoter DNA, including the inhibition of VapC by VapB and linear conformation of bound DNA in the VapBC complex. The complexation of VapBC with the linear DNA is not consistent with known structures of VapBC homologs in complex with bent DNA. We also identified VapC from S. Typhimurium LT2 as a putative Ca2+ -dependent ribonuclease, which differs from previous data showing that VapC homologs have Mg2+ or Mn2+ -dependent ribonuclease activities. The present studies could provide structural understanding of the physiology of VapBC systems and foundation for the development of new antibiotic drugs against Salmonella infection.
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Affiliation(s)
- DongWon Park
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, Republic of Korea
| | - Hye-Jin Yoon
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
| | - Ki-Young Lee
- Department of Medical Biophysics, University of Toronto, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Sung-Jean Park
- College of Pharmacy, Gachon University, Incheon, Republic of Korea
| | - Seung-Ho Cheon
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, Republic of Korea
| | - Hyung Ho Lee
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul, Republic of Korea
| | - Sang Jae Lee
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, Korea
| | - Bong-Jin Lee
- The Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, Republic of Korea
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Conformation and Domain Movement Analysis of Human Matrix Metalloproteinase-2: Role of Associated Zn 2+ and Ca 2+ Ions. Int J Mol Sci 2019; 20:ijms20174194. [PMID: 31461891 PMCID: PMC6747341 DOI: 10.3390/ijms20174194] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/20/2019] [Accepted: 08/26/2019] [Indexed: 12/23/2022] Open
Abstract
Matrix metaloproteinase-2 (MMP-2) is an extracellular Zn2+ protease specific to type I and IV collagens. Its expression is associated with several inflammatory, degenerative, and malignant diseases. Conformational properties, domain movements, and interactions between MMP-2 and its associated metal ions were characterized using a 1.0 µs molecular dynamics simulation. Dihedral principle component analysis revealed ten families of conformations with the greatest degree of variability occurring in the link region connecting the catalytic and hemopexin domains. Dynamic cross-correlation analysis indicated domain movements corresponding to the opening and closing of the hemopexin domain in relation to the fibronectin and catalytic domains facilitated by the link region. Interaction energies were calculated using the molecular mechanics Poisson Boltzman surface area-interaction entropy (MMPBSA-IE) analysis method and revealed strong binding energies for the catalytic Zn2+ ion 1, Ca2+ ion 1, and Ca2+ ion 3 with significant conformational stability at the binding sites of Zn2+ ion 1 and Ca2+ ion 1. Ca2+ ion 2 diffuses freely away from its crystallographically defined binding site. Zn2+ ion 2 plays a minor role in conformational stability of the catalytic domain while Ca2+ ion 3 is strongly attracted to the highly electronegative sidechains of the Asp residues around the central β-sheet core of the hemopexin domain; however, the interacting residue sidechain carboxyl groups are outside of Ca2+ ion 3′s coordination sphere.
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Jiang H, Zhang W, Chen F, Zou J, Chen W, Huang G. Purification of an iron-binding peptide from scad (Decapterus maruadsi) processing by-products and its effects on iron absorption by Caco-2 cells. J Food Biochem 2019; 43:e12876. [PMID: 31353718 DOI: 10.1111/jfbc.12876] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/07/2019] [Accepted: 04/10/2019] [Indexed: 11/29/2022]
Abstract
This work was aimed at producing peptides containing iron-binding capabilities from scad (Decapterus maruadsi) processing by-product with alcalase hydrolysis. The chelating peptides were purified by ultrafiltration, immobilized-metal affinity chromatography, gel filtration chromatography, and reversed-phase high-performance liquid chromatography. A novel iron-binding peptide was purified with 1,386.63 Da molecular weight and amino acid sequence of QKGTYDDYVEGL. The peptide binds to iron mainly through carboxyl and hydroxyl oxygen bonds. The iron-binding peptide can significantly promote the absorption of inorganic iron in Caco-2 cells. These results have contributed to development of the peptide from scad processing by-products hydrolyzate in iron supplementations. PRACTICAL APPLICATIONS: Iron deficiency is one of the most common and widespread nutritional disorders in the world. Iron-peptide chelates may be suitable for iron-fortification. Our study shows that a peptide purified from scad processing by-product has iron-chelating activity, and significantly increases iron absorption by Caco-2 cells. Hence, this peptide has potential application as a novel carrier for enhancing iron absorption.
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Affiliation(s)
- Han Jiang
- Key Laboratory of Marine Food Quality and Hazard Controlling Technology of Zhejiang Province, College of Life Sciences, China Jiliang University, Hangzhou, China
| | - Wenting Zhang
- Dong Cheng Elementary School affiliated to Hangzhou Normal University, Hangzhou, China
| | - Fangyuan Chen
- Key Laboratory of Marine Food Quality and Hazard Controlling Technology of Zhejiang Province, College of Life Sciences, China Jiliang University, Hangzhou, China
| | - Jiong Zou
- Key Laboratory of Marine Food Quality and Hazard Controlling Technology of Zhejiang Province, College of Life Sciences, China Jiliang University, Hangzhou, China
| | - Wenwei Chen
- Key Laboratory of Marine Food Quality and Hazard Controlling Technology of Zhejiang Province, College of Life Sciences, China Jiliang University, Hangzhou, China
| | - Guangrong Huang
- Key Laboratory of Marine Food Quality and Hazard Controlling Technology of Zhejiang Province, College of Life Sciences, China Jiliang University, Hangzhou, China
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18
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Guo C, Cheng M, Gross ML. Protein-Metal-Ion Interactions Studied by Mass Spectrometry-Based Footprinting with Isotope-Encoded Benzhydrazide. Anal Chem 2018; 91:1416-1423. [PMID: 30495934 DOI: 10.1021/acs.analchem.8b04088] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Metal ions, usually bound by various amino-acid side chains in proteins, play multiple roles in protein folding, conformational change, cellular communication, and catalysis. Ca(II) and Mg(II), abundant among biologically relevant cations, execute their cellular functions associated with the conformational change of bound proteins. They bind with proteins where carboxylic acid residues are dominant ligands. To develop mass spectrometry for mapping protein-binding sites, we implemented a new carboxyl group footprinter, benzhydrazide, and refined it with isotope encoding. The method uses carbodiimide chemistry to footprint carboxylic residues, whereby 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide activates a carboxyl group followed by nucleophilic attack by benzhydrazide forming a stable labeled product. We tested the effectiveness of isotope-encoded benzhydrazide by studying Ca2+ and Mg2+ binding of calmodulin, an EF-hand protein. The footprinting results indicate that the four active sites for metal-ion binding (EF hands I, II, III, and IV) and the linker region (peptide 78-86) undergo conformational changes upon Ca(II) and Mg(II) binding, respectively. The outcome is consistent with previously reported results and 3-D structures, thereby validating a new reagent that is more reactive and discriminating for specific amino-acid protein footprinting. This reagent should be important for locating metal-binding sites of other metalloproteins.
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Affiliation(s)
- Chunyang Guo
- Department of Chemistry , Washington University , St. Louis , Missouri 63130 , United States
| | - Ming Cheng
- Department of Chemistry , Washington University , St. Louis , Missouri 63130 , United States
| | - Michael L Gross
- Department of Chemistry , Washington University , St. Louis , Missouri 63130 , United States
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19
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Jing Z, Liu C, Qi R, Ren P. Many-body effect determines the selectivity for Ca 2+ and Mg 2+ in proteins. Proc Natl Acad Sci U S A 2018; 115:E7495-E7501. [PMID: 30038003 PMCID: PMC6094099 DOI: 10.1073/pnas.1805049115] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Calcium ion is a versatile messenger in many cell-signaling processes. To achieve their functions, calcium-binding proteins selectively bind Ca2+ against a background of competing ions such as Mg2+ The high specificity of calcium-binding proteins has been intriguing since Mg2+ has a higher charge density than Ca2+ and is expected to bind more tightly to the carboxylate groups in calcium-binding pockets. Here, we showed that the specificity for Ca2+ is dictated by the many-body polarization effect, which is an energetic cost arising from the dense packing of multiple residues around the metal ion. Since polarization has stronger distance dependence compared with permanent electrostatics, the cost associated with the smaller Mg2+ is much higher than that with Ca2+ and outweighs the electrostatic attraction favorable for Mg2+ With the AMOEBA (atomic multipole optimized energetics for biomolecular simulation) polarizable force field, our simulations captured the relative binding free energy between Ca2+ and Mg2+ for proteins with various types of binding pockets and explained the nonmonotonic size dependence of the binding free energy in EF-hand proteins. Without electronic polarization, the smaller ions are always favored over larger ions and the relative binding free energy is roughly proportional to the net charge of the pocket. The many-body effect depends on both the number and the arrangement of charged residues. Fine-tuning of the ion selectivity could be achieved by combining the many-body effect and geometric constraint.
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Affiliation(s)
- Zhifeng Jing
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712
| | - Chengwen Liu
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712
| | - Rui Qi
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712
| | - Pengyu Ren
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX 78712
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20
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Revisiting paradigms of Ca2+ signaling protein kinase regulation in plants. Biochem J 2018; 475:207-223. [DOI: 10.1042/bcj20170022] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 12/07/2017] [Accepted: 12/08/2017] [Indexed: 12/15/2022]
Abstract
Calcium (Ca2+) serves as a universal second messenger in eukaryotic signal transduction. Understanding the Ca2+ activation kinetics of Ca2+ sensors is critical to understanding the cellular signaling mechanisms involved. In this review, we discuss the regulatory properties of two sensor classes: the Ca2+-dependent protein kinases (CPKs/CDPKs) and the calcineurin B-like (CBL) proteins that control the activity of CBL-interacting protein kinases (CIPKs) and identify emerging topics and some foundational points that are not well established experimentally. Most plant CPKs are activated by physiologically relevant Ca2+ concentrations except for those with degenerate EF hands, and new results suggest that the Ca2+-dependence of kinase activation may be modulated by both protein–protein interactions and CPK autophosphorylation. Early results indicated that activation of plant CPKs by Ca2+ occurred by relief of autoinhibition. However, recent studies of protist CDPKs suggest that intramolecular interactions between CDPK domains contribute allosteric control to CDPK activation. Further studies are required to elucidate the mechanisms regulating plant CPKs. With CBL–CIPKs, the two major activation mechanisms are thought to be (i) binding of Ca2+-bound CBL to the CIPK and (ii) phosphorylation of residues in the CIPK activation loop. However, the relative importance of these two mechanisms in regulating CIPK activity is unclear. Furthermore, information detailing activation by physiologically relevant [Ca2+] is lacking, such that the paradigm of CBLs as Ca2+ sensors still requires critical, experimental validation. Developing models of CPK and CIPK regulation is essential to understand how these kinases mediate Ca2+ signaling and to the design of experiments to test function in vivo.
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21
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Park DJ, Koh PO. Diabetes aggravates decreases in hippocalcin and parvalbumin expression in focal cerebral ischemia. Neurosci Lett 2017; 662:189-194. [PMID: 29061397 DOI: 10.1016/j.neulet.2017.10.039] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 09/27/2017] [Accepted: 10/19/2017] [Indexed: 11/24/2022]
Abstract
Hyperglycemia is a major risk factor for stroke and increases brain damage during ischemic stroke. Hyperglycemia increases the intracellular calcium concentration after ischemic injury, thereby triggering neuronal cell death. Calcium binding proteins, including hippocalcin and parvalbumin, are critical regulators of intracellular calcium levels. This study aimed to investigate whether hyperglycemic conditions affect hippocalcin and parvalbumin expression during ischemic brain injury. Male adult rats were treated intraperitoneally with streptozotocin (40mg/kg) to induce hyperglycemia. Four weeks later, cerebral ischemic injury was induced via surgical middle cerebral artery occlusion (MCAO). Cerebral cortex samples were collected 24h after MCAO. A proteomic approach showed that the protein levels of hippocalcin and parvalbumin were significantly decreased in streptozotocin-treated animals with MCAO injury compared to streptozotocin-treated animals and animals that underwent MCAO alone. Reverse transcription-PCR and Western blot analyses clearly confirmed the decreased levels of these proteins. These decreases indicate dysregulation of the intracellular calcium balance and induction of cell death. Thus, these results suggest that significantly decreased levels of hippocalcin and parvalbumin exacerbate neuronal cell death in diabetic animals with ischemic brain injury.
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Affiliation(s)
- Dong-Ju Park
- Department of Anatomy, College of Veterinary Medicine, Research Institute of Life Science, Gyeongsang National University, 501 Jinjudaero, Jinju 660-701, South Korea
| | - Phil-Ok Koh
- Department of Anatomy, College of Veterinary Medicine, Research Institute of Life Science, Gyeongsang National University, 501 Jinjudaero, Jinju 660-701, South Korea.
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22
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A novel calcium-binding peptide from Antarctic krill protein hydrolysates and identification of binding sites of calcium-peptide complex. Food Chem 2017; 243:389-395. [PMID: 29146354 DOI: 10.1016/j.foodchem.2017.09.152] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 09/27/2017] [Accepted: 09/29/2017] [Indexed: 11/22/2022]
Abstract
Trypsin was used for preparing peptides with high calcium-binding capacity from Antarctic krill. Hydroxyapatite chromatography (HAC), size-exclusion chromatography (SEC), and reversed phase high performance liquid chromatography (RP-HPLC) were used to capture and purify calcium-binding peptides. The peptide sequence was determined to be VLGYIQIR (N- to C-terminal, MW = 960.58 Da), using LTQ Orbitrap XL. According to the results of FTIR and mass spectrometry, chelating site of calcium ions may possibly involve the carbonal or amino groups of Gln, Ile and Arg residues. Molecular dynamic simulation showed the conformation of peptide was markedly varied, and the distance between calcium ion and Gln and Ile residues was changing all the time. However, the distance between calcium ion and carboxyl oxygen of arginine residues was not changed significantly from 2 ns to 100 ns. Identified peptide can be used as a novel calcium supplement.
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23
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Trans-omics approaches used to characterise fish nutritional biorhythms in leopard coral grouper (Plectropomus leopardus). Sci Rep 2017; 7:9372. [PMID: 28839183 PMCID: PMC5570933 DOI: 10.1038/s41598-017-09531-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 07/14/2017] [Indexed: 01/21/2023] Open
Abstract
Aquaculture is now a major supplier of fish, and has the potential to be a major source of protein in the future. Leopard coral groupers are traded in Asian markets as superior fish, and production via aquaculture has commenced. As feeding efficiency is of great concern in aquaculture, we sought to examine the metabolism of leopard coral groupers using trans-omics approaches. Metabolic mechanisms were comprehensively analysed using transcriptomic and metabolomic techniques. This study focused on the dynamics of muscular metabolites and gene expression. The omics data were discussed in light of circadian rhythms and fasting/feeding. The obtained data suggest that branched-chain amino acids played a role in energy generation in the fish muscle tissues during fasting. Moreover, glycolysis, TCA cycles, and purine metabolic substances exhibited circadian patterns, and gene expression also varied. This study is the first step to understanding the metabolic mechanisms of the leopard coral grouper.
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The Involvement of Mg 2+ in Regulation of Cellular and Mitochondrial Functions. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:6797460. [PMID: 28757913 PMCID: PMC5516748 DOI: 10.1155/2017/6797460] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 05/31/2017] [Indexed: 12/11/2022]
Abstract
Mg2+ is an essential mineral with pleotropic impacts on cellular physiology and functions. It acts as a cofactor of several important enzymes, as a regulator of ion channels such as voltage-dependent Ca2+ channels and K+ channels and on Ca2+-binding proteins. In general, Mg2+ is considered as the main intracellular antagonist of Ca2+, which is an essential secondary messenger initiating or regulating a great number of cellular functions. This review examines the effects of Mg2+ on mitochondrial functions with a particular focus on energy metabolism, mitochondrial Ca2+ handling, and apoptosis.
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25
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Asp ML, Sjaastad FV, Siddiqui JK, Davis JP, Metzger JM. Effects of Modified Parvalbumin EF-Hand Motifs on Cardiac Myocyte Contractile Function. Biophys J 2017; 110:2094-105. [PMID: 27166817 DOI: 10.1016/j.bpj.2016.03.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 03/28/2016] [Accepted: 03/31/2016] [Indexed: 10/21/2022] Open
Abstract
Cardiac gene delivery of parvalbumin (Parv), an EF-hand Ca(2+) buffer, has been studied as a therapeutic strategy for diastolic heart failure, in which slow Ca(2+) reuptake is an important contributor. A limitation of wild-type (WT) Parv is the significant trade-off between faster relaxation and blunted contraction amplitude, occurring because WT-Parv sequesters Ca(2+) too early in the cardiac cycle and prematurely truncates sarcomere shortening in the facilitation of rapid relaxation. We recently demonstrated that an E → Q substitution (ParvE101Q) at amino acid 12 of the EF-hand Ca(2+)/Mg(2+) binding loop disrupts bidentate Ca(2+) binding, reducing Ca(2+) affinity by 99-fold and increasing Mg(2+) affinity twofold. ParvE101Q caused faster relaxation and not only preserved contractility, but unexpectedly increased it above untreated myocytes. To gain mechanistic insight into the increased contractility, we focused here on amino acid 12 of the EF-hand motif. We introduced an E → D substitution (ParvE101D) at this site, which converts bidentate Ca(2+) coordination to monodentate coordination. ParvE101D decreased Ca(2+) affinity by 114-fold and increased Mg(2+) affinity 28-fold compared to WT-Parv. ParvE101D increased contraction amplitude compared to both untreated myocytes and myocytes with ParvE101Q, with limited improvement in relaxation. Additionally, ParvE101D increased spontaneous contractions after pacing stress. ParvE101D also increased Ca(2+) transient peak height and was diffusely localized around the Z-line of the sarcomere, suggesting a Ca(2+)-dependent mechanism of enhanced contractility. Sarcoplasmic reticulum Ca(2+) load was not changed with ParvE101D, but postpacing Ca(2+) waves were increased. Together, these data show that inverted Ca(2+)/Mg(2+) binding affinities of ParvE101D increase myocyte contractility through a Ca(2+)-dependent mechanism without altering sarcoplasmic reticulum Ca(2+) load and by increasing unstimulated contractions and Ca(2+) waves. ParvE101D provides mechanistic insight into how changes in the Ca(2+)/Mg(2+) binding affinities of parvalbumin's EF-hand motif alter function of cardiac myocytes. These data are informative in developing new Ca(2+) buffering strategies for the failing heart.
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Affiliation(s)
- Michelle L Asp
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Frances V Sjaastad
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Jalal K Siddiqui
- Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, Ohio
| | - Jonathan P Davis
- Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, Ohio
| | - Joseph M Metzger
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota.
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26
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Liao J, Deng J, Qin Z, Tang J, Shu M, Ding C, Liu J, Hu C, Yuan M, Huang Y, Yang R, Zhou Y. Genome-Wide Identification and Analyses of Calmodulins and Calmodulin-like Proteins in Lotus japonicas. FRONTIERS IN PLANT SCIENCE 2017; 8:482. [PMID: 28424729 PMCID: PMC5380670 DOI: 10.3389/fpls.2017.00482] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 03/20/2017] [Indexed: 05/10/2023]
Abstract
L. japonicus, a model plant of legumes plants, is widely used in symbiotic nitrogen fixation. A large number of studies on it have been published based on the genetic, biochemical, structural studies. These results are secondhand reports that CaM is a key regulator during Rhizobial infection. In plants, there are multiple CaM genes encoding several CaM isoforms with only minor amino acid differences. Moreover, the regulation mechanism of this family of proteins during rhizobia infection is still unclear. In the current study, a family of genes encoding CaMs and CMLs that possess only the Ca2+-binding EF-hand motifs were analyzed. Using ML and BI tree based on amino acid sequence similarity, seven loci defined as CaMs and 19 CMLs, with at least 23% identity to CaM, were identified. The phylogenetics, gene structures, EF hand motif organization, and expression characteristics were evaluated. Seven CaM genes, encoding only 4 isoforms, were found in L. japonicus. According to qRT-PCR, four LjCaM isoforms are involved in different rhizobia infection stages. LjCaM1 might be involved in the early rhizobia infection epidermal cells stage. Furthermore, additional structural differences and expression behaviors indicated that LjCMLs may have different potential functions from LjCaMs.
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Affiliation(s)
- Jinqiu Liao
- College of Life Sciences, Sichuan Agricultural UniversityYaan, China
| | - Jiabin Deng
- School of Geography and Tourism, Guizhou Education UniversityGuiyang, China
| | - Zongzhi Qin
- College of Life Sciences, Sichuan Agricultural UniversityYaan, China
| | - Jiayong Tang
- Animal Nutrition Institute, Sichuan Agricultural UniversityChengdu, China
| | - Maorong Shu
- College of Life Sciences, Sichuan Agricultural UniversityYaan, China
| | - Chunbang Ding
- College of Life Sciences, Sichuan Agricultural UniversityYaan, China
| | - Jing Liu
- College of Life Sciences, Sichuan Agricultural UniversityYaan, China
| | - Chao Hu
- College of Life Sciences, Sichuan Agricultural UniversityYaan, China
| | - Ming Yuan
- College of Life Sciences, Sichuan Agricultural UniversityYaan, China
| | - Yan Huang
- College of Life Sciences, Sichuan Agricultural UniversityYaan, China
| | - Ruiwu Yang
- College of Life Sciences, Sichuan Agricultural UniversityYaan, China
| | - Yonghong Zhou
- Triticeae Research Institute, Sichuan Agricultural UniversityChengdu, China
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27
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Uroshlev L, Kulakovskiy I, Esipova N, Tumanyan V, Rahmanov S, Makeev V. Role of structural water for prediction of cation binding sites in apoproteins. J Biomol Struct Dyn 2017; 36:221-232. [DOI: 10.1080/07391102.2016.1273136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- L.A. Uroshlev
- Department of Computational Systems Biology, Vavilov Institute of General Genetics, 3 Gubkina st., Moscow 119991, Russian Federation
| | - I.V. Kulakovskiy
- Department of Computational Systems Biology, Vavilov Institute of General Genetics, 3 Gubkina st., Moscow 119991, Russian Federation
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 32 Vavilova st., Moscow 119991, Russian Federation
| | - N.G. Esipova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 32 Vavilova st., Moscow 119991, Russian Federation
| | - V.G. Tumanyan
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 32 Vavilova st., Moscow 119991, Russian Federation
| | - S.V. Rahmanov
- Department of Computational Systems Biology, Vavilov Institute of General Genetics, 3 Gubkina st., Moscow 119991, Russian Federation
| | - V.J. Makeev
- Department of Computational Systems Biology, Vavilov Institute of General Genetics, 3 Gubkina st., Moscow 119991, Russian Federation
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 32 Vavilova st., Moscow 119991, Russian Federation
- State Research Institute of Genetics and Selection of Industrial Microorganisms, GosNIIGenetika, 1st Dorozhniy proezd 1, Moscow 117545, Russian Federation
- Department of Medical and Biological Physics, Moscow Institute of Physics and Technology, 9 Institutskiy per., Moscow 141700, Russian Federation
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DePalma JW, Kelleher PJ, Tavares LC, Johnson MA. Coordination-Dependent Spectroscopic Signatures of Divalent Metal Ion Binding to Carboxylate Head Groups: H 2- and He-Tagged Vibrational Spectra of M 2+·RCO 2¯ (M = Mg and Ca, R = -CD 3, -CD 2CD 3) Complexes. J Phys Chem Lett 2017; 8:484-488. [PMID: 28060510 DOI: 10.1021/acs.jpclett.6b02964] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We explore the intramolecular distortions present in divalent metal ion-carboxylate ion pairs using vibrational spectroscopy of the cryogenically cooled, mass-selected species isolated in the gas phase. The spectral signatures of the C-O stretching modes are identified using the perdeutero isotopologues of the acetate and propionate anions to avoid congestion arising from the CH2 fundamentals. Both Ca2+ and Mg2+ are observed to bind in a symmetrical, so-called "bidentate" arrangement to the -CO2¯ group. The very strong deformations of the head groups displayed by the binary complexes dramatically relax when either neutral water molecules or counterions are attached to the Mg2+RCO2¯ cation. These results emphasize the critical role that local coordination plays when using the RCO2¯ bands to deduce the metal ion complexation motif in condensed media.
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Affiliation(s)
- Joseph W DePalma
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Patrick J Kelleher
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
| | - Laís C Tavares
- Instituto de Química, Universidade de São Paulo , Caixa Postal 26077, São Paulo, CEP 05508-900, Brazil
| | - Mark A Johnson
- Sterling Chemistry Laboratory, Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
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Huang F, Luo J, Ning T, Cao W, Jin X, Zhao H, Wang Y, Han S. Cytosolic and Nucleosolic Calcium Signaling in Response to Osmotic and Salt Stresses Are Independent of Each Other in Roots of Arabidopsis Seedlings. FRONTIERS IN PLANT SCIENCE 2017; 8:1648. [PMID: 28983313 PMCID: PMC5613247 DOI: 10.3389/fpls.2017.01648] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 09/07/2017] [Indexed: 05/02/2023]
Abstract
Calcium acts as a universal second messenger in both developmental processes and responses to environmental stresses. Previous research has shown that a number of stimuli can induce [Ca2+] increases in both the cytoplasm and nucleus in plants. However, the relationship between cytosolic and nucleosolic calcium signaling remains obscure. Here, we generated transgenic plants containing a fusion protein, comprising rat parvalbumin (PV) with either a nuclear export sequence (PV-NES) or a nuclear localization sequence (NLS-PV), to selectively buffer the cytosolic or nucleosolic calcium. Firstly, we found that the osmotic stress-induced cytosolic [Ca2+] increase (OICIcyt) and the salt stress-induced cytosolic [Ca2+] increase (SICIcyt) were impaired in the PV-NES lines compared with the Arabidopsis wildtype (WT). Similarly, the osmotic stress-induced nucleosolic [Ca2+] increase (OICInuc) and salt stress-induced nucleosolic [Ca2+] increase (SICInuc) were also disrupted in the NLS-PV lines. These results indicate that PV can effectively buffer the increase of [Ca2+] in response to various stimuli in Arabidopsis. However, the OICIcyt and SICIcyt in the NLS-PV plants were similar to those in the WT, and the OICInuc and SICInuc in the PV-NES plants were also same as those in the WT, suggesting that the cytosolic and nucleosolic calcium dynamics are mutually independent. Furthermore, we found that osmotic stress- and salt stress-inhibited root growth was reduced dramatically in the PV-NES and NLS-PV lines, while the osmotic stress-induced increase of the lateral root primordia was higher in the PV-NES plants than either the WT or NLS-PV plants. In addition, several stress-responsive genes, namely CML37, DREB2A, MYB2, RD29A, and RD29B, displayed diverse expression patterns in response to osmotic and salt stress in the PV-NES and NLS-PV lines when compared with the WT. Together, these results imply that the cytosolic and nucleosolic calcium signaling coexist to play the pivotal roles in the growth and development of plants and their responses to environment stresses.
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Decoding the Interactions Regulating the Active State Mechanics of Eukaryotic Protein Kinases. PLoS Biol 2016; 14:e2000127. [PMID: 27902690 PMCID: PMC5130182 DOI: 10.1371/journal.pbio.2000127] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Accepted: 10/24/2016] [Indexed: 02/07/2023] Open
Abstract
Eukaryotic protein kinases regulate most cellular functions by phosphorylating targeted protein substrates through a highly conserved catalytic core. In the active state, the catalytic core oscillates between open, intermediate, and closed conformations. Currently, the intramolecular interactions that regulate the active state mechanics are not well understood. Here, using cAMP-dependent protein kinase as a representative model coupled with biochemical, biophysical, and computational techniques, we define a set of highly conserved electrostatic and hydrophobic interactions working harmoniously to regulate these mechanics. These include the previously identified salt bridge between a lysine from the β3-strand and a glutamate from the αC-helix as well as an electrostatic interaction between the phosphorylated activation loop and αC-helix and an ensemble of hydrophobic residues of the Regulatory spine and Shell. Moreover, for over three decades it was thought that the highly conserved β3-lysine was essential for phosphoryl transfer, but our findings show that the β3-lysine is not required for phosphoryl transfer but is essential for the active state mechanics. Eukaryotic protein kinases (EPKs) regulate over a third of the human proteome by transferring the γ-phosphate from adenosine triphosphate (ATP) to a protein substrate in a process known as protein phosphorylation. Biochemical and biophysical studies have shown that EPKs undergo multiconformational rearrangements in which the catalytic core is oscillating between open, intermediate, and closed conformations when active. Presently, the intramolecular interactions that regulate this dynamic process are not well understood. In this paper, we show how a set of conserved electrostatic and hydrophobic interactions harmoniously regulate the active state mechanics. The electrostatic interactions involve the highly conserved salt bridge between the lysine from subdomain-II and glutamate from subdomain-III as well as an interaction between the activation loop and αC-helix. The hydrophobic interactions include the nonlinear motifs known as the Regulatory spine and Shell that traverse both lobes of the catalytic core. Furthermore, our findings show that the highly conserved “catalytic lysine” is not directly required for phosphoryl transfer but rather serves as a hub that aligns and positions the dynamic core elements required for catalysis.
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31
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Kucharski AN, Scott CE, Davis JP, Kekenes-Huskey PM. Understanding Ion Binding Affinity and Selectivity in β-Parvalbumin Using Molecular Dynamics and Mean Spherical Approximation Theory. J Phys Chem B 2016; 120:8617-30. [PMID: 27267153 DOI: 10.1021/acs.jpcb.6b02666] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Parvalbumin (PV) is a globular calcium (Ca(2+))-selective protein expressed in a variety of biological tissues. Our computational studies of the rat β-parvalbumin (β-PV) isoform seek to elucidate the molecular thermodynamics of Ca(2+) versus magnesium (Mg(2+)) binding at the protein's two EF-hand motifs. Specifically, we have utilized molecular dynamics (MD) simulations and a mean-field electrolyte model (mean spherical approximation (MSA) theory) to delineate how the EF-hand scaffold controls the "local" thermodynamics of Ca(2+) binding selectivity over Mg(2+). Our MD simulations provide the probability density of metal-chelating oxygens within the EF-hand scaffolds for both Ca(2+) and Mg(2+), as well the conformational strain induced by Mg(2+) relative to Ca(2+) binding. MSA theory utilizes the binding domain oxygen and charge distributions to predict the chemical potential of ion binding, as well as their corresponding concentrations within the binding domain. We find that the electrostatic and steric contributions toward ion binding were similar for Mg(2+) and Ca(2+), yet the latter was 5.5 kcal/mol lower in enthalpy when internal strain within the EF hand was considered. We therefore speculate that beyond differences in dehydration energies for the Ca(2+) versus Mg(2+), strain induced in the β-PV EF hand by cation binding significantly contributes to the nearly 10,000-fold difference in binding affinity reported in the literature. We further complemented our analyses of local factors governing cation binding selectivity with whole-protein (global) contributions, such as interhelical residue-residue contacts and solvent exposure of hydrophobic surface. These contributions were found to be comparable for both Ca(2+)- and Mg(2+)-bound β-PV, which may implicate local factors, EF-hand strain, and dehydration, in providing the primary means of selectivity. We anticipate these methods could be used to estimate metal binding thermodynamics across a broad range of PV sequence homologues and EF-hand-containing, Ca(2+) binding proteins.
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Affiliation(s)
- Amir N Kucharski
- Department of Chemistry, University of Kentucky , Lexington, Kentucky 40506, United States
| | - Caitlin E Scott
- Department of Chemistry, University of Kentucky , Lexington, Kentucky 40506, United States
| | - Jonathan P Davis
- Department of Physiology and Cell Biology, Ohio State University , Columbus, Ohio 43210, United States
| | - Peter M Kekenes-Huskey
- Department of Chemistry, University of Kentucky , Lexington, Kentucky 40506, United States
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Dubey P, Murab S, Karmakar S, Chowdhury PK, Ghosh S. Modulation of Self-Assembly Process of Fibroin: An Insight for Regulating the Conformation of Silk Biomaterials. Biomacromolecules 2015; 16:3936-44. [PMID: 26575529 DOI: 10.1021/acs.biomac.5b01258] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Controlling the mechanism of self-assembly in proteins has emerged as a potent tool for various biomedical applications. Silk fibroin self-assembly consists of gradual conformational transition from random coil to β-sheet structure. In this work we elucidated the intermediate secondary conformation in the presence of Ca(2+) ions during fibroin self-assembly. The interaction of fibroin and calcium ions resulted in a predominantly α-helical intermediate conformation, which was maintained to certain extent even in the final conformation as illustrated by circular dichroism and attenuated total reflectance-Fourier transform infrared spectroscopy. Further, to elucidate the mechanism behind this interaction molecular modeling of the N-terminal region of fibroin with Ca(2+) ions was performed. Negatively charged glutamate and aspartate amino acids play a key role in the electrostatic interaction with positively charged calcium ions. Therefore, insights about modulation of self-assembly mechanism of fibroin could potentially be utilized to develop silk-based biomaterials consisting of the desired secondary conformation.
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Affiliation(s)
- Priyanka Dubey
- Department of Textile Technology and ‡Department of Chemistry, Indian Institute of Technology Delhi , Hauz Khas, New Delhi 110016, India
| | - Sumit Murab
- Department of Textile Technology and ‡Department of Chemistry, Indian Institute of Technology Delhi , Hauz Khas, New Delhi 110016, India
| | - Sandip Karmakar
- Department of Textile Technology and ‡Department of Chemistry, Indian Institute of Technology Delhi , Hauz Khas, New Delhi 110016, India
| | - Pramit K Chowdhury
- Department of Textile Technology and ‡Department of Chemistry, Indian Institute of Technology Delhi , Hauz Khas, New Delhi 110016, India
| | - Sourabh Ghosh
- Department of Textile Technology and ‡Department of Chemistry, Indian Institute of Technology Delhi , Hauz Khas, New Delhi 110016, India
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Han L, Tian R, Yan H, Pei L, Hou Z, Hao S, Li YV, Tian Q, Liu B, Zhang Q. Hydrogen-rich water protects against ischemic brain injury in rats by regulating calcium buffering proteins. Brain Res 2015; 1615:129-138. [PMID: 25920370 DOI: 10.1016/j.brainres.2015.04.038] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 04/16/2015] [Accepted: 04/20/2015] [Indexed: 10/23/2022]
Abstract
Hydrogen-rich water (HRW) has anti-oxidant activities, and it exerts neuroprotective effects during ischemia-reperfusion brain injury. Parvalbumin and hippocalcin are two calcium buffering proteins, which are involved in neuronal differentiation, maturation and apoptosis. The aim of this study was to investigate whether HRW could moderate parvalbumin and hippocalcin expression during ischemic brain injury and glutamate toxicity-induced neuronal cell death. Focal brain ischemia was induced in male Sprague-Dawley rats by middle cerebral artery occlusion (MCAO). Rats were treated with H2O or HRW (6 ml/kg per rat) before and after MCAO, and cerebral cortical tissues were collected 1, 7 and 14 days after MCAO. Based on our results, HRW treatment was able to reduce brain infarct volume and improve neurological function following ischemic brain injury. In addition, HRW prevented the ischemia-induced reduction of parvalbumin and hippocalcin levels in vivo and also reduced the glutamate toxicity-induced death of neurons, including the dose-dependent reduction of glutamate toxicity-associated proteins in vitro. Moreover, HRW attenuated the glutamate toxicity-induced elevate in intracellular Ca(2+) levels. All these results suggest that HRW could protect against ischemic brain injury and that the maintenance of parvalbumin and hippocalcin levels by HRW during ischemic brain injury might contribute to the neuroprotective effects against neuron damage.
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Affiliation(s)
- Li Han
- Department of Neurology, Liyuan Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, PR China
| | - Runfa Tian
- Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, Tiantan Xili 6, Dongcheng District, Beijing 100050, PR China
| | - Huanhuan Yan
- Key Laboratory of Neurological Diseases of Ministry of Education, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, PR China
| | - Lei Pei
- Department of Physiology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, PR China; Department of Pathology and Pathophysiology, School of Basic Medicine, Institute for Brain Research, Huazhong University of Science and Technology, Wuhan 430000, PR China
| | - Zonggang Hou
- Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, Tiantan Xili 6, Dongcheng District, Beijing 100050, PR China
| | - Shuyu Hao
- Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, Tiantan Xili 6, Dongcheng District, Beijing 100050, PR China
| | - Yang V Li
- Department of Biomedical Sciences, Ohio University Heritage College of Osteopathic Medicine, Athens, OH 45701, USA
| | - Qing Tian
- Department of Pathology and Pathophysiology, School of Basic Medicine, Institute for Brain Research, Huazhong University of Science and Technology, Wuhan 430000, PR China; Department of Pathophysiology, Key Laboratory of Ministry of Education of Neurological Diseases, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, PR China
| | - Baiyun Liu
- Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, Tiantan Xili 6, Dongcheng District, Beijing 100050, PR China; Neurotrauma Laboratory, Beijing Neurosurgical Institute, Capital Medical University, Beijing 100050, PR China.
| | - Qi Zhang
- Department of Neurology, Liyuan Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430000, PR China; Department of Pathology and Pathophysiology, School of Basic Medicine, Institute for Brain Research, Huazhong University of Science and Technology, Wuhan 430000, PR China.
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34
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Saxena A, García AE. Multisite ion model in concentrated solutions of divalent cations (MgCl2 and CaCl2): osmotic pressure calculations. J Phys Chem B 2015; 119:219-27. [PMID: 25482831 PMCID: PMC4291043 DOI: 10.1021/jp507008x] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 12/03/2014] [Indexed: 01/09/2023]
Abstract
Accurate force field parameters for ions are essential for meaningful simulation studies of proteins and nucleic acids. Currently accepted models of ions, especially for divalent ions, do not necessarily reproduce the right physiological behavior of Ca(2+) and Mg(2+) ions. Saxena and Sept (J. Chem. Theor. Comput. 2013, 9, 3538-3542) described a model, called the multisite-ion model, where instead of treating the ions as an isolated sphere, the charge was split into multiple sites with partial charge. This model provided accurate inner shell coordination of the ion with biomolecules and predicted better free energies for proteins and nucleic acids. Here, we expand and refine the multisite model to describe the behavior of divalent ions in concentrated MgCl2 and CaCl2 electrolyte solutions, eliminating the unusual ion-ion pairing and clustering of ions which occurred in the original model. We calibrate and improve the parameters of the multisite model by matching the osmotic pressure of concentrated solutions of MgCl2 to the experimental values and then use these parameters to test the behavior of CaCl2 solutions. We find that the concentrated solutions of both divalent ions exhibit the experimentally observed behavior with correct osmotic pressure, the presence of solvent separated ion pairs instead of direct ion pairs, and no aggregation of ions. The improved multisite model for (Mg(2+) and Ca(2+)) can be used in classical simulations of biomolecules at physiologically relevant salt concentrations.
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Affiliation(s)
- Akansha Saxena
- Department of Physics, Applied
Physics, and Astronomy and The Center for Biotechnology and Interdisciplinary
Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Angel E. García
- Department of Physics, Applied
Physics, and Astronomy and The Center for Biotechnology and Interdisciplinary
Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
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35
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Chen L, Zhang H, Sun J, Wong YH, Han Z, Au DWT, Bajic VB, Qian PY. Proteomic changes in brain tissues of marine medaka (Oryzias melastigma) after chronic exposure to two antifouling compounds: butenolide and 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2014; 157:47-56. [PMID: 25456219 DOI: 10.1016/j.aquatox.2014.09.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 09/21/2014] [Accepted: 09/23/2014] [Indexed: 06/04/2023]
Abstract
SeaNine 211 with active ingredient of 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT) has been used as a "green" antifouling agent worldwide but has raised serious biosafety concerns in coastal environments. DCOIT has the potential to disrupt the neurotransmission in nervous system, but the underlying mechanism has not been clarified. In the present study, we used TMT six-plex labeling coupled with two-dimensional LC-MS/MS analysis to investigate the protein expression profiles in brain tissues of the marine medaka (Oryzias melastigma) after a 28-day exposure to environmentally-realistic concentration of DCOIT at 2.55 μg/L (0.009 μM) or butenolide, one promising antifouling compound, at 2.31 μg/L (0.012 μM). DCOIT and butenolide induced differential expression of 26 and 18 proteins in male brains and of 27 and 23 proteins in female brains, respectively. Distinct mechanisms of toxicity were initiated by DCOIT and butenolide in males, whereas the protein expression profiles were largely similar in females treated by these two compounds. In males, DCOIT exposure mainly led to disruption of mitogen-activated protein kinase (MAPK) signaling pathway, while butenolide affected proteins related to the cytoskeletal disorganization that is considered as a general response to toxicant stress. Furthermore, a sex-dependent protein expression profile was also noted between male and female fish, as evident by the inverse changes in the expressions of common proteins (5 proteins for butenolide- and 2 proteins for DCOIT-exposed fish). Overall, this study provided insight into the molecular mechanisms underlying the toxicity of DCOIT and butenolide. The extremely low concentrations used in this study highlighted the ecological relevance, arguing for thorough assessments of their ecological risks before the commercialization of any new antifouling compound.
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Affiliation(s)
- Lianguo Chen
- Division of Life Science and Environmental Science Programs, Hong Kong University of Science and Technology, Hong Kong, China
| | - Huoming Zhang
- Biosciences Core Laboratory, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Jin Sun
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Yue-Him Wong
- Division of Life Science and Environmental Science Programs, Hong Kong University of Science and Technology, Hong Kong, China
| | - Zhuang Han
- Division of Life Science and Environmental Science Programs, Hong Kong University of Science and Technology, Hong Kong, China
| | - Doris W T Au
- State Key Laboratory in Marine Pollution, Department of Biology and Chemistry, City University of Hong Kong, Hong Kong, China
| | - Vladimir B Bajic
- Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Pei-Yuan Qian
- Division of Life Science and Environmental Science Programs, Hong Kong University of Science and Technology, Hong Kong, China.
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36
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Lapidus SH, Rajput NN, Qu X, Chapman KW, Persson KA, Chupas PJ. Solvation structure and energetics of electrolytes for multivalent energy storage. Phys Chem Chem Phys 2014; 16:21941-5. [DOI: 10.1039/c4cp03015j] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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37
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Sheftic SR, White E, Gage DJ, Alexandrescu AT. NMR structure of the HWE kinase associated response regulator Sma0114 in its activated state. Biochemistry 2014; 53:311-22. [PMID: 24364624 DOI: 10.1021/bi401497h] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bacterial receiver domains modulate intracellular responses to external stimuli in two-component systems. Sma0114 is the first structurally characterized representative from the family of receiver domains that are substrates for histidine-tryptophan-glutamate (HWE) kinases. We report the NMR structure of Sma0114 bound by Ca(2+) and BeF3(-), a phosphate analogue that stabilizes the activated state. Differences between the NMR structures of the inactive and activated states occur in helix α1, the active site loop that connects strand β3 and helix α3, and in the segment from strand β5 to helix α5 of the 455 (α4-β5-α5) face. Structural rearrangements of the 455 face typically make receiver domains competent for binding downstream target molecules. In Sma0114 the structural changes accompanying activation result in a more negatively charged surface for the 455 face. Coupling between the 455 face and active site phosphorylation is usually mediated through the rearrangement of a threonine and tyrosine residue, in a mechanism called Y-T coupling. The NMR structure indicates that Sma0114 lacks Y-T coupling and that communication between the active site and the 455 face is achieved through a conserved lysine residue that stabilizes the acyl phosphate in receiver domains. (15)N-NMR relaxation experiments were used to investigate the backbone dynamics of the Sma0114 apoprotein, the binary Sma0114·Ca(2+) complex, and the ternary Sma0114·Ca(2+)·BeF3(-) complex. The loss of entropy due to ligand binding at the active site is compensated by increased flexibility in the 455 face. The dynamic character of the 455 face in Sma0114, which results in part from the replacement of helix α4 by a flexible loop, may facilitate induced-fit recognition of target molecules.
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Affiliation(s)
- Sarah R Sheftic
- Department of Molecular and Cellular Biology, University of Connecticut, Storrs , Connecticut, United States
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38
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RONG Z, MA L, LIU B, TIAN Y, YANG B. Electrochemistry of Eu(III) Binding to N-terminal of Euplotes Octocarinatus Centrin. ELECTROCHEMISTRY 2014. [DOI: 10.5796/electrochemistry.82.663] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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39
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Fuson K, Rice A, Mahling R, Snow A, Nayak K, Shanbhogue P, Meyer AG, Redpath GMI, Hinderliter A, Cooper ST, Sutton RB. Alternate splicing of dysferlin C2A confers Ca²⁺-dependent and Ca²⁺-independent binding for membrane repair. Structure 2013; 22:104-15. [PMID: 24239457 DOI: 10.1016/j.str.2013.10.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 09/27/2013] [Accepted: 10/01/2013] [Indexed: 12/01/2022]
Abstract
Dysferlin plays a critical role in the Ca²⁺-dependent repair of microlesions that occur in the muscle sarcolemma. Of the seven C2 domains in dysferlin, only C2A is reported to bind both Ca²⁺ and phospholipid, thus acting as a key sensor in membrane repair. Dysferlin C2A exists as two isoforms, the "canonical" C2A and C2A variant 1 (C2Av1). Interestingly, these isoforms have markedly different responses to Ca²⁺ and phospholipid. Structural and thermodynamic analyses are consistent with the canonical C2A domain as a Ca²⁺-dependent, phospholipid-binding domain, whereas C2Av1 would likely be Ca²⁺-independent under physiological conditions. Additionally, both isoforms display remarkably low free energies of stability, indicative of a highly flexible structure. The inverted ligand preference and flexibility for both C2A isoforms suggest the capability for both constitutive and Ca²⁺-regulated effector interactions, an activity that would be essential in its role as a mediator of membrane repair.
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Affiliation(s)
- Kerry Fuson
- Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Anne Rice
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth 55812 MN, USA
| | - Ryan Mahling
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth 55812 MN, USA
| | - Adam Snow
- Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Kamakshi Nayak
- Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Prajna Shanbhogue
- Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Austin G Meyer
- Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Gregory M I Redpath
- Institute for Neuroscience and Muscle Research, Children's Hospital at Westmead, Sydney, NSW 2145, Australia
| | - Anne Hinderliter
- Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth 55812 MN, USA
| | - Sandra T Cooper
- Institute for Neuroscience and Muscle Research, Children's Hospital at Westmead, Sydney, NSW 2145, Australia
| | - R Bryan Sutton
- Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.
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40
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Tatsumi C, Okamoto K. Molecular genetic investigation of dental attrition in mice. PEDIATRIC DENTAL JOURNAL 2013. [DOI: 10.1016/j.pdj.2013.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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41
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Corry B. Na(+)/Ca(2+) selectivity in the bacterial voltage-gated sodium channel NavAb. PeerJ 2013; 1:e16. [PMID: 23638350 PMCID: PMC3629057 DOI: 10.7717/peerj.16] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 01/04/2013] [Indexed: 02/03/2023] Open
Abstract
The recent publication of a number of high resolution bacterial voltage-gated sodium channel structures has opened the door for the mechanisms employed by these channels to distinguish between ions to be elucidated. The way these channels select between Na+ and K+ has been investigated in computational studies, but the selectivity for Na+ over Ca2+ has not yet been studied in this way. Here we use molecular dynamics simulations to calculate the energetics of Na+ and Ca2+ transport through the channel. Single ion profiles show that Ca2+ experiences a large barrier midway through the selectivity filter that is not seen by Na+. This barrier is caused by the need for Ca2+ to partly dehydrate to pass through this region and the lack of compensating interactions with the protein. Multi-ion profiles show that ions can pass each other in the channel, which is why the presence of Ca2+ does not block Na+ conduction despite binding more strongly in the pore.
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Affiliation(s)
- Ben Corry
- Research School of Biology , The Australian National University , Acton , Australia
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Chen ML. Two-dimensional gel electrophoresis revealed antipsychotic drugs induced protein expression modulations in C6 glioma cells. Prog Neuropsychopharmacol Biol Psychiatry 2013; 40:1-11. [PMID: 22960606 DOI: 10.1016/j.pnpbp.2012.08.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 08/22/2012] [Accepted: 08/22/2012] [Indexed: 01/13/2023]
Abstract
The efficacy and side effects of long-term administration of antipsychotic drugs (APDs) may be attributed to drug-induced change in protein expression in brain cells. Glial cells are non-neuronal cells that can provide nutrients and physiological support to neuronal cells. Glial cells are believed to participate in neurotransmission, neurons' early development, and guiding migration of neurons. Accumulated clinical data also indicate relationships between disturbance of glial cells' function and various psychotic diseases including schizophrenia. We used two-dimensional gel electrophoresis coupled with MALDI-TOF/TOF mass spectrometry protein identification to analyze differentially expressed proteins in haloperidol-, risperidone-, and clozapine-treated C6 glioma cells. We found that the expression of pericentrin, glial fibrillary acidic protein, Rho GDP-dissociation inhibitor 1, anionic trypsin-1, peroxiredoxin-1, and parvalbumin were regulated by each of the three APDs. Western blot analysis supported the findings. Real-time quantitative PCR detected changed transcriptions of those proteins. Protein and gene expression of N-cadherin in C6 cells were affected by haloperidol and clozapine but not risperidone. In addition, regulatory effects of clozapine on the glyceraldehyde 3-phosphate dehydrogenase gene were observed in C6 cells. This may be the first study to uncover how APD-modulated genes may cause protein expression changes and affect ARHGDIA-mediated regulation of Rho GTPase family proteins in glial cells.
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Affiliation(s)
- Mao-Liang Chen
- Department of Research, Buddhist Tzu Chi General Hospital, Taipei Branch, New Taipei City, Taiwan, ROC.
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Abstract
Melatonin has anti-oxidant activity and it exerts a neuroprotective effects during ischemic brain injury. Calcium-buffering proteins including parvalbumin and hippocalcin are involved in neuronal differentiation and maturation through calcium signaling. This study investigated whether melatonin moderates parvalbumin and hippocalcin expression in cerebral ischemia and glutamate toxicity-induced neuronal cell death. Focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO). Male Sprague-Dawley rats were treated with vehicle or melatonin (5 mg/kg) prior to MCAO, and cerebral cortical tissues were collected 24 hr after MCAO. Parvalbumin and hippocalcin levels were decreased in vehicle-treated animal with MCAO, whereas melatonin prevented the ischemic injury-induced reduction in these proteins. In cultured hippocampal cells, glutamate toxicity decreased parvalbumin and hippocalcin levels, while melatonin treatment prevented the glutamate exposure-induced diminished in these proteins levels. Melatonin also attenuated the glutamate toxicity-induced increase in intracellular Ca(2+) levels. These results suggest that the maintenance of parvalbumin and hippocalcin levels by melatonin in ischemic injury contributes to the neuroprotective effect of melatonin against neuronal cell damage.
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Affiliation(s)
- Phil-Ok Koh
- Department of Anatomy, College of Veterinary Medicine and Research Institute of Life Science, Gyeongsang National University, Jinju, South Korea.
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44
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Enzymatic preparation and characterization of iron-chelating peptides from anchovy (Engraulis japonicus) muscle protein. Food Res Int 2012. [DOI: 10.1016/j.foodres.2012.04.013] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Bakunts AG. Metal-specific structural changes in parvalbumin. Biochem Biophys Res Commun 2012; 424:730-5. [PMID: 22809511 DOI: 10.1016/j.bbrc.2012.07.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 07/08/2012] [Indexed: 10/28/2022]
Abstract
Parvalbumin is a small protein of EF-hand family whose main role is considered to be metal buffering. Recent evidences indicate that parvalbumin also fulfills more complicated functions, which may be determined by the diversity in structural changes in response to the binding of different metal cations. In the present work the conformations of α and β isoforms of pike parvalbumin in the Ca(2+)- and Mg(2+)-loaded state were studied by intrinsic fluorescence, circular dichroism and bis-ANS extrinsic fluorescence. We have determined the structural region causing different spectral response on the binding of Mg(2+)- and Ca(2+) ions in pike β-parvalbumin. Our data reveal similarity of the metal-bound forms of α-parvalbumin. In contrast, those of β isoform differ significantly in the tyrosine spectral range. We also discuss the possible physiological consequences of the structural rearrangements accompanied Mg(2+)/Ca(2+) exchange in pike β-parvalbumin.
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Affiliation(s)
- Anush G Bakunts
- Institute for Biological Instrumentation of the Russian Academy of Sciences, Institutskaya Str. 7, Pushchino, Moscow Region 142290, Russia.
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46
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Senguen FT, Grabarek Z. X-ray structures of magnesium and manganese complexes with the N-terminal domain of calmodulin: insights into the mechanism and specificity of metal ion binding to an EF-hand. Biochemistry 2012; 51:6182-94. [PMID: 22803592 DOI: 10.1021/bi300698h] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Calmodulin (CaM), a member of the EF-hand superfamily, regulates many aspects of cell function by responding specifically to micromolar concentrations of Ca(2+) in the presence of an ~1000-fold higher concentration of cellular Mg(2+). To explain the structural basis of metal ion binding specificity, we have determined the X-ray structures of the N-terminal domain of calmodulin (N-CaM) in complexes with Mg(2+), Mn(2+), and Zn(2+). In contrast to Ca(2+), which induces domain opening in CaM, octahedrally coordinated Mg(2+) and Mn(2+) stabilize the closed-domain, apo-like conformation, while tetrahedrally coordinated Zn(2+) ions bind at the protein surface and do not compete with Ca(2+). The relative positions of bound Mg(2+) and Mn(2+) within the EF-hand loops are similar to those of Ca(2+); however, the Glu side chain at position 12 of the loop, whose bidentate interaction with Ca(2+) is critical for domain opening, does not bind directly to either Mn(2+) or Mg(2+), and the vacant ligand position is occupied by a water molecule. We conclude that this critical interaction is prevented by specific stereochemical constraints imposed on the ligands by the EF-hand β-scaffold. The structures suggest that Mg(2+) contributes to the switching off of calmodulin activity and possibly other EF-hand proteins at the resting levels of Ca(2+). The Mg(2+)-bound N-CaM structure also provides a unique view of a transiently bound hydrated metal ion and suggests a role for the hydration water in the metal-induced conformational change.
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Affiliation(s)
- F Timur Senguen
- Boston Biomedical Research Institute, Watertown, MA 02472, USA
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Soupene E, Kuypers FA. Phosphatidylcholine formation by LPCAT1 is regulated by Ca(2+) and the redox status of the cell. BMC BIOCHEMISTRY 2012; 13:8. [PMID: 22676268 PMCID: PMC3439698 DOI: 10.1186/1471-2091-13-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 05/25/2012] [Indexed: 12/21/2022]
Abstract
Background Unsaturated fatty acids are susceptible to oxidation and damaged chains are removed from glycerophospholipids by phospholipase A2. De-acylated lipids are then re-acylated by lysophospholipid acyltransferase enzymes such as LPCAT1 which catalyses the formation of phosphatidylcholine (PC) from lysoPC and long-chain acyl-CoA. Results Activity of LPCAT1 is inhibited by Ca2+, and a Ca2+-binding motif of the EF-hand type, EFh-1, was identified in the carboxyl-terminal domain of the protein. The residues Asp-392 and Glu-403 define the loop of the hairpin structure formed by EFh-1. Substitution of D392 and E403 to alanine rendered an enzyme insensitive to Ca2+, which established that Ca2+ binding to that region negatively regulates the activity of the acyltransferase amino-terminal domain. Residue Cys-211 of the conserved motif III is not essential for catalysis and not sufficient for sensitivity to treatment by sulfhydryl-modifier agents. Among the several active cysteine-substitution mutants of LPCAT1 generated, we identified one to be resistant to treatment by sulfhydryl-alkylating and sulfhydryl-oxidizer agents. Conclusion Mutant forms of LPCAT1 that are not inhibited by Ca2+ and sulfhydryl-alkylating and –oxidizing agents will provide a better understanding of the physiological function of a mechanism that places the formation of PC, and the disposal of the bioactive species lysoPC, under the control of the redox status and Ca2+ concentration of the cell.
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Affiliation(s)
- Eric Soupene
- Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr, Way, Oakland, CA 94609, USA.
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Experimental and DFT Studies on Poly[di-μ3-acesulfamato-O,O:O′;O′:O,O-di-μ-acesulfamato-O,O; N-di-μ-aqua-dicalcium(II)] Complex. J Inorg Organomet Polym Mater 2012. [DOI: 10.1007/s10904-012-9679-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Cuello S, Ximénez-Embún P, Ruppen I, Schonthaler HB, Ashman K, Madrid Y, Luque-Garcia JL, Cámara C. Analysis of protein expression in developmental toxicity induced by MeHg in zebrafish. Analyst 2012; 137:5302-11. [DOI: 10.1039/c2an35913h] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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50
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Chinpongpanich A, Wutipraditkul N, Thairat S, Buaboocha T. Biophysical characterization of calmodulin and calmodulin-like proteins from rice, Oryza sativa L. Acta Biochim Biophys Sin (Shanghai) 2011; 43:867-76. [PMID: 21908855 DOI: 10.1093/abbs/gmr081] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Calmodulin (CaM) transduces the increase in cytosolic Ca(2+) concentrations by binding to and altering the activities of target proteins, thereby affecting the physiological responses to the vast array of stimuli. Here, we examined the purified recombinant proteins encoded by three Cam and eight Cam-like (CML) genes from rice. With the exception of one OsCML, all recombinant proteins could be purified by Ca(2+)-dependent hydrophobic chromatography and exhibited an electrophoretic mobility shift when incubated with Ca(2+). The three CaMs all bound CaM kinase II peptide, but none of the eight CMLs did, suggesting a possible differential target binding between the CaM and CML proteins. In addition, their conformational changes upon Ca(2+)-binding were evaluated by circular dichroism spectroscopy and fluorescence spectroscopy using 8-Anilino-1-naphthalene-sulfonic acid. Taken together, OsCMLs were found exhibiting a spectrum of both structural and functional characteristics that ranged from typical to atypical of CaMs. From structural comparison, the OsCMLs have overall main-chain conformation nearly identical to OsCaMs, but with distinct distribution of some charged and hydrophobic amino acids on their target-binding site. These results suggest that genetic polymorphism has promoted the functional diversity of the OsCML family, whose members possess modes of actions probably different from, though maybe overlapping with, those of OsCaMs.
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Affiliation(s)
- Aumnart Chinpongpanich
- Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand
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