1
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Verteramo ML, Ignjatović MM, Kumar R, Wernersson S, Ekberg V, Wallerstein J, Carlström G, Chadimová V, Leffler H, Zetterberg F, Logan DT, Ryde U, Akke M, Nilsson UJ. Interplay of halogen bonding and solvation in protein-ligand binding. iScience 2024; 27:109636. [PMID: 38633000 PMCID: PMC11021960 DOI: 10.1016/j.isci.2024.109636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/13/2024] [Accepted: 03/26/2024] [Indexed: 04/19/2024] Open
Abstract
Halogen bonding is increasingly utilized in efforts to achieve high affinity and selectivity of molecules designed to bind proteins, making it paramount to understand the relationship between structure, dynamics, and thermodynamic driving forces. We present a detailed analysis addressing this problem using a series of protein-ligand complexes involving single halogen substitutions - F, Cl, Br, and I - and nearly identical structures. Isothermal titration calorimetry reveals an increasingly favorable binding enthalpy from F to I that correlates with the halogen size and σ-hole electropositive character, but is partially counteracted by unfavorable entropy, which is constant from F to Cl and Br, but worse for I. Consequently, the binding free energy is roughly equal for Cl, Br, and I. QM and solvation-free-energy calculations reflect an intricate balance between halogen bonding, hydrogen bonds, and solvation. These advances have the potential to aid future drug design initiatives involving halogenated compounds.
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Affiliation(s)
| | | | - Rohit Kumar
- Department of Chemistry, Lund University, Lund, Sweden
| | | | | | | | | | | | - Hakon Leffler
- Microbiology, Immunology, and Glycobiology, Department of Experimental Medicine, Lund University, Lund, Sweden
| | | | | | - Ulf Ryde
- Department of Chemistry, Lund University, Lund, Sweden
| | - Mikael Akke
- Department of Chemistry, Lund University, Lund, Sweden
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2
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Tasić M, Ivković J, Carlström G, Melcher M, Bollella P, Bendix J, Gorton L, Persson P, Uhlig J, Strand D. Electro-mechanically switchable hydrocarbons based on [8]annulenes. Nat Commun 2022; 13:860. [PMID: 35165264 PMCID: PMC8844043 DOI: 10.1038/s41467-022-28384-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 01/13/2022] [Indexed: 11/11/2022] Open
Abstract
Pure hydrocarbons with shape and conjugation properties that can be switched by external stimuli is an intriguing prospect in the design of new responsive materials and single-molecule electronics. Here, we develop an oligomeric [8]annulene-based material that combines a remarkably efficient topological switching upon redox changes with structural simplicity, stability, and straightforward synthesis: 5,12-alkyne linked dibenzo[a,e]cyclooctatetraenes (dbCOTs). Upon reduction, the structures accommodate a reversible reorganization from a pseudo-conjugated tub-shape to a conjugated aromatic system. This switching in oligomeric structures gives rise to multiple defined states that are deconvoluted by electrochemical, NMR, and optical methods. The combination of stable electromechanical responsivity and ability to relay electrons stepwise through an extended (pseudo-conjugated) π-system in partially reduced structures validate alkyne linked dbCOTs as a practical platform for developing new responsive materials and switches based on [8]annulene cores. Pure hydrocarbons with properties that can be switched by external stimuli are interesting for the design and development of new responsive materials. Here, the authors develop an oligomeric [8]annulene-based material that combines topological switching upon redox changes with structural simplicity, stability, and straightforward synthesis.
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3
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Wernersson S, Carlström G, Jakobsson A, Akke M. Rapid measurement of heteronuclear transverse relaxation rates using non-uniformly sampled R1ρ accordion experiments. Magn Reson (Gott) 2021; 2:571-587. [PMID: 37905216 PMCID: PMC10539792 DOI: 10.5194/mr-2-571-2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 06/28/2021] [Indexed: 11/01/2023]
Abstract
Multidimensional, heteronuclear NMR relaxation methods are used extensively to characterize the dynamics of biological macromolecules. Acquisition of relaxation datasets on proteins typically requires significant measurement time, often several days. Accordion spectroscopy offers a powerful means to shorten relaxation rate measurements by encoding the "relaxation dimension" into the indirect evolution period in multidimensional experiments. Time savings can also be achieved by non-uniform sampling (NUS) of multidimensional NMR data, which is used increasingly to improve spectral resolution or increase sensitivity per unit time. However, NUS is not commonly implemented in relaxation experiments, because most reconstruction algorithms are inherently nonlinear, leading to problems when estimating signal intensities, relaxation rate constants and their error bounds. We have previously shown how to avoid these shortcomings by combining accordion spectroscopy with NUS, followed by data reconstruction using sparse exponential mode analysis, thereby achieving a dramatic decrease in the total length of longitudinal relaxation experiments. Here, we present the corresponding transverse relaxation experiment, taking into account the special considerations required for its successful implementation in the framework of the accordion-NUS approach. We attain the highest possible precision in the relaxation rate constants by optimizing the NUS scheme with respect to the Cramér-Rao lower bound of the variance of the estimated parameter, given the total number of sampling points and the spectrum-specific signal characteristics. The resulting accordion-NUS R 1 ρ relaxation experiment achieves comparable precision in the parameter estimates compared to conventional CPMG (Carr-Purcell-Meiboom-Gill) R 2 or spin-lock R 1 ρ experiments while saving an order of magnitude in experiment time.
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Affiliation(s)
- Sven Wernersson
- Biophysical Chemistry, Center for Molecular Protein Science,
Department of Chemistry, Lund University, P.O. Box 124, 22100 Lund, Sweden
| | - Göran Carlström
- Centre for Analysis and Synthesis, Department of Chemistry, Lund
University, P.O. Box 124, 22100 Lund, Sweden
| | - Andreas Jakobsson
- Department of Mathematical Statistics, Lund University, P.O. Box 118,
22100 Lund, Sweden
| | - Mikael Akke
- Biophysical Chemistry, Center for Molecular Protein Science,
Department of Chemistry, Lund University, P.O. Box 124, 22100 Lund, Sweden
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4
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Teze D, Zhao J, Wiemann M, Kazi ZGA, Lupo R, Zeuner B, Vuillemin M, Rønne ME, Carlström G, Duus JØ, Sanejouand YH, O'Donohue MJ, Nordberg Karlsson E, Fauré R, Stålbrand H, Svensson B. Rational Enzyme Design without Structural Knowledge: A Sequence-Based Approach for Efficient Generation of Transglycosylases. Chemistry 2021; 27:10323-10334. [PMID: 33914359 DOI: 10.1002/chem.202100110] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Indexed: 12/22/2022]
Abstract
Glycobiology is dogged by the relative scarcity of synthetic, defined oligosaccharides. Enzyme-catalysed glycosylation using glycoside hydrolases is feasible but is hampered by the innate hydrolytic activity of these enzymes. Protein engineering is useful to remedy this, but it usually requires prior structural knowledge of the target enzyme, and/or relies on extensive, time-consuming screening and analysis. Here, a straightforward strategy that involves rational rapid in silico analysis of protein sequences is described. The method pinpoints 6-12 single-mutant candidates to improve transglycosylation yields. Requiring very little prior knowledge of the target enzyme other than its sequence, the method is generic and procures catalysts for the formation of glycosidic bonds involving various d/l-, α/β-pyranosides or furanosides, and exo or endo action. Moreover, mutations validated in one enzyme can be transposed to others, even distantly related enzymes.
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Affiliation(s)
- David Teze
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, building 224, DK-2800, Kongens Lyngby, Denmark
| | - Jiao Zhao
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, 135 avenue de Rangueil, 31077, Toulouse CEDEX 04, France
| | - Mathias Wiemann
- Department of Biochemistry and Structural Biology, Lund University, 221 00, Lund, Sweden
| | - Zubaida G A Kazi
- Department of Chemistry, Lund University, PO Box 124, 22100, Lund, Sweden
| | - Rossana Lupo
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, building 224, DK-2800, Kongens Lyngby, Denmark
| | - Birgitte Zeuner
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, building 224, DK-2800, Kongens Lyngby, Denmark
| | - Marlène Vuillemin
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, building 224, DK-2800, Kongens Lyngby, Denmark
| | - Mette E Rønne
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, building 224, DK-2800, Kongens Lyngby, Denmark
| | - Göran Carlström
- Department of Chemistry, Lund University, PO Box 124, 22100, Lund, Sweden
| | - Jens Ø Duus
- Department of Chemistry, Technical University of Denmark, Kemitorvet, bulding 207, DK-2800, Kongens Lyngby, Denmark
| | - Yves-Henri Sanejouand
- UFIP, UMR 6286, Université de Nantes, CNRS, 2, chemin de la Houssiniere, Nantes, France
| | - Michael J O'Donohue
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, 135 avenue de Rangueil, 31077, Toulouse CEDEX 04, France
| | | | - Régis Fauré
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, 135 avenue de Rangueil, 31077, Toulouse CEDEX 04, France
| | - Henrik Stålbrand
- Department of Biochemistry and Structural Biology, Lund University, 221 00, Lund, Sweden
| | - Birte Svensson
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, building 224, DK-2800, Kongens Lyngby, Denmark
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5
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Gaspar R, Idini I, Carlström G, Linse S, Sparr E. Transient Lipid-Protein Structures and Selective Ganglioside Uptake During α-Synuclein-Lipid Co-aggregation. Front Cell Dev Biol 2021; 9:622764. [PMID: 33681202 PMCID: PMC7930334 DOI: 10.3389/fcell.2021.622764] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 01/28/2021] [Indexed: 01/02/2023] Open
Abstract
α-Synuclein is a membrane-interacting protein involved in Parkinson's disease. Here we have investigated the co-association of α-synuclein and lipids from ganglioside-containing model membranes. Our study relies on the reported importance of ganglioside lipids, which are found in high amounts in neurons and exosomes, on cell-to-cell prion-like transmission of misfolded α-synuclein. Samples taken along various stages of the aggregation process were imaged using cryogenic transmission electron microscopy, and the composition of samples corresponding to the final state analyzed using NMR spectroscopy. The combined data shows that α-synuclein co-assembles with lipids from the ganglioside (GM1)-containing model membranes. The lipid-protein samples observed during the aggregation process contain non-vesicular objects not present at the final stage, thus capturing the co-existence of species under non-equilibrium conditions. A range of different lipid-protein co-assemblies are observed during the time course of the reaction and some of these appear to be transient assemblies that evolve into other co-aggregates over time. At the end of the aggregation reaction, the samples become more homogeneous, showing thin fibrillar structures heavily decorated with small vesicles. From the NMR analysis, we conclude that the ratio of GM1 to phosphatidyl choline (PC) in the supernatant of the co-aggregated samples is significantly reduced compared to the GM1/PC ratio of the lipid dispersion from which these samples were derived. Taken together, this indicates a selective uptake of GM1 into the fibrillar aggregates and removal of GM1-rich objects from the solution.
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Affiliation(s)
- Ricardo Gaspar
- Division of Physical Chemistry, Department of Chemistry, Lund University, Lund, Sweden.,Division of Biochemistry and Structural Biology, Department of Chemistry, Lund University, Lund, Sweden
| | - Ilaria Idini
- Division of Physical Chemistry, Department of Chemistry, Lund University, Lund, Sweden
| | - Göran Carlström
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Lund, Sweden
| | - Sara Linse
- Division of Biochemistry and Structural Biology, Department of Chemistry, Lund University, Lund, Sweden
| | - Emma Sparr
- Division of Physical Chemistry, Department of Chemistry, Lund University, Lund, Sweden
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6
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König N, Willner L, Carlström G, Zinn T, Knudsen KD, Rise F, Topgaard D, Lund R. Spherical Micelles with Nonspherical Cores: Effect of Chain Packing on the Micellar Shape. Macromolecules 2020; 53:10686-10698. [PMID: 33335341 PMCID: PMC7735752 DOI: 10.1021/acs.macromol.0c01936] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/23/2020] [Indexed: 11/30/2022]
Abstract
Self-assembly of amphiphilic polymers into micelles is an archetypical example of a "self-confined" system due to the formation of micellar cores with dimensions of a few nanometers. In this work, we investigate the chain packing and resulting shape of C n -PEOx micelles with semicrystalline cores using small/wide-angle X-ray scattering (SAXS/WAXS), contrast-variation small-angle neutron scattering (SANS), and nuclear magnetic resonance spectroscopy (NMR). Interestingly, the n-alkyl chains adopt a rotator-like conformation and pack into prolate ellipses (axial ratio ϵ ≈ 0.5) in the "crystalline" region and abruptly arrange into a more spheroidal shape (ϵ ≈ 0.7) above the melting point. We attribute the distorted spherical shape above the melting point to thermal fluctuations and intrinsic rigidity of the n-alkyl blocks. We also find evidence for a thin dehydrated PEO layer (≤1 nm) close to the micellar core. The results provide substantial insight into the interplay between crystallinity and molecular packing in confinement and the resulting overall micellar shape.
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Affiliation(s)
- Nico König
- Department
of Chemistry, University of Oslo, P.O. Box 1033, Blindern, 0315 Oslo, Norway
- Jülich
Centre for Neutron Science (JCNS-1) and Institute of Biological Information
Processing (IBI-8), Forschungszentrum Jülich
GmbH, 52425 Jülich, Germany
| | - Lutz Willner
- Jülich
Centre for Neutron Science (JCNS-1) and Institute of Biological Information
Processing (IBI-8), Forschungszentrum Jülich
GmbH, 52425 Jülich, Germany
| | - Göran Carlström
- Centre
for Analysis and Synthesis, Department of Chemistry, Lund University, P.O. Box 124, 22100 Lund, Sweden
| | - Thomas Zinn
- ESRF
- The European Synchrotron, 38043 Grenoble, France
| | - Kenneth D. Knudsen
- Department
for Neutron Materials Characterization, Institute for Energy Technology, P.O. Box 40, 2027 Kjeller, Norway
| | - Frode Rise
- Department
of Chemistry, University of Oslo, P.O. Box 1033, Blindern, 0315 Oslo, Norway
| | - Daniel Topgaard
- Division
of Physical Chemistry, Department of Chemistry, Lund University, Lund, Sweden
| | - Reidar Lund
- Department
of Chemistry, University of Oslo, P.O. Box 1033, Blindern, 0315 Oslo, Norway
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7
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Köhler C, Carlström G, Gunnarsson A, Weininger U, Tångefjord S, Ullah V, Lepistö M, Karlsson U, Papavoine T, Edman K, Akke M. Dynamic allosteric communication pathway directing differential activation of the glucocorticoid receptor. Sci Adv 2020; 6:eabb5277. [PMID: 32832645 PMCID: PMC7439413 DOI: 10.1126/sciadv.abb5277] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 06/05/2020] [Indexed: 05/07/2023]
Abstract
Allosteric communication within proteins is a hallmark of biochemical signaling, but the dynamic transmission pathways remain poorly characterized. We combined NMR spectroscopy and surface plasmon resonance to reveal these pathways and quantify their energetics in the glucocorticoid receptor, a transcriptional regulator controlling development, metabolism, and immune response. Our results delineate a dynamic communication network of residues linking the ligand-binding pocket to the activation function-2 interface, where helix 12, a switch for transcriptional activation, exhibits ligand- and coregulator-dependent dynamics coupled to graded activation. The allosteric free energy responds to variations in ligand structure: subtle changes gradually tune allostery while preserving the transmission pathway, whereas substitution of the entire pharmacophore leads to divergent allosteric control by apparently rewiring the communication network. Our results provide key insights that should aid in the design of mechanistically differentiated ligands.
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Affiliation(s)
- C. Köhler
- Respiratory, Inflammation and Autoimmunity, Pharmaceutical Sciences, R&D, AstraZeneca, Gothenburg, Sweden
| | - G. Carlström
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, P.O. Box 124, 221 00 Lund, Sweden
| | - A. Gunnarsson
- Discovery Sciences, Pharmaceutical Sciences, R&D, AstraZeneca, Gothenburg, Sweden
| | - U. Weininger
- Division of Biophysical Chemistry, Center for Molecular Protein Science, Department of Chemistry, Lund University, P. O. Box 124, 221 00 Lund, Sweden
| | - S. Tångefjord
- Respiratory, Inflammation and Autoimmunity, Pharmaceutical Sciences, R&D, AstraZeneca, Gothenburg, Sweden
- Discovery Sciences, Pharmaceutical Sciences, R&D, AstraZeneca, Gothenburg, Sweden
| | - V. Ullah
- Respiratory, Inflammation and Autoimmunity, Pharmaceutical Sciences, R&D, AstraZeneca, Gothenburg, Sweden
| | - M. Lepistö
- Respiratory, Inflammation and Autoimmunity, Pharmaceutical Sciences, R&D, AstraZeneca, Gothenburg, Sweden
| | - U. Karlsson
- Discovery Sciences, Pharmaceutical Sciences, R&D, AstraZeneca, Gothenburg, Sweden
| | - T. Papavoine
- Respiratory, Inflammation and Autoimmunity, Pharmaceutical Sciences, R&D, AstraZeneca, Gothenburg, Sweden
| | - K. Edman
- Discovery Sciences, Pharmaceutical Sciences, R&D, AstraZeneca, Gothenburg, Sweden
| | - M. Akke
- Division of Biophysical Chemistry, Center for Molecular Protein Science, Department of Chemistry, Lund University, P. O. Box 124, 221 00 Lund, Sweden
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8
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Pham QD, Carlström G, Lafon O, Sparr E, Topgaard D. Quantification of the amount of mobile components in intact stratum corneum with natural-abundance 13C solid-state NMR. Phys Chem Chem Phys 2020; 22:6572-6583. [PMID: 32159206 DOI: 10.1039/d0cp00079e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The outermost layer of the skin is the stratum corneum (SC), which is mainly comprised of solid proteins and lipids. Minor amounts of mobile proteins and lipids are crucial for the macroscopic properties of the SC, including softness, elasticity and barrier function. Still this minor number of mobile components are not well characterized in terms of structure or amount. Conventional quantitative direct polarization (Q-DP) 13C solid-state NMR gives signal amplitudes proportional to concentrations, but fails to quantify the SC mobile components because of spectral overlap with the overwhelming signals from the solids. Spectral editing with the INEPT scheme suppresses the signals from solids, but also modulates the amplitudes of the mobile components depending on their values of the transverse relaxation times T2, scalar couplings JCH, and number of covalently bound hydrogens nH. This study describes a quantitative INEPT (Q-INEPT) method relying on systematic variation of the INEPT timing variables to estimate T2, JCH, nH, and amplitude for each of the resolved resonances from the mobile components. Q-INEPT is validated with a series of model systems containing molecules with different hydrophobicity and dynamics. For selected systems where Q-DP is applicable, the results of Q-INEPT and Q-DP are similar with respect to the linearity and uncertainty of the obtained molar ratios. Utilizing a reference compound with known concentration, we quantify the concentrations of mobile lipids and proteins within the mainly solid SC. By melting all lipids at high temperature, we obtain the total lipid concentration. These Q-INEPT results are the first steps towards a quantitative understanding of the relations between mobile component concentrations and SC macroscopic properties.
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Affiliation(s)
- Quoc Dat Pham
- Division of Physical Chemistry, Chemistry Department, Lund University, Lund, Sweden and Department of Food Technology, Lund University, Lund, Sweden
| | - Göran Carlström
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Lund, Sweden
| | - Olivier Lafon
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, UMR 8181-UCCS-Unité de Catalyse et Chimie du Solide, F-59000 Lille, France and Institut Universitaire de France (IUF), Paris, France
| | - Emma Sparr
- Division of Physical Chemistry, Chemistry Department, Lund University, Lund, Sweden
| | - Daniel Topgaard
- Division of Physical Chemistry, Chemistry Department, Lund University, Lund, Sweden
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9
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Peng F, Månsson LK, Holm SH, Ghosh S, Carlström G, Crassous JJ, Schurtenberger P, Tegenfeldt JO. A Droplet-Based Microfluidics Route to Temperature-Responsive Colloidal Molecules. J Phys Chem B 2019; 123:9260-9271. [PMID: 31584820 DOI: 10.1021/acs.jpcb.9b07754] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Small clusters of spherical colloids that mimic real molecules, so-called colloidal molecules, hold great promise as building blocks in bottom-up routes to new materials. However, their typical hard sphere nature has hampered their assembly into ordered structures, largely due to a lack of control in the interparticle interactions. To provide easy external control of the interactions, the present work focuses on the preparation of colloidal molecules from temperature-responsive microgel particles that undergo a transition from a soft repulsive to a short-range attractive state as their characteristic volume phase transition temperature (VPTT) is crossed. Preparation of the colloidal molecules starts with the use of a droplet-based microfluidics device to form highly uniform water-in-oil (W/O) emulsion droplets containing, on average and with a narrow distribution, four microgels per droplet. Evaporation of the water then leads to the formation of colloidal molecule-like clusters, which can be harvested following cross-linking and phase transfer. We use a mixture of two types of microgels, one based on poly(N-isopropylacrylamide) (PNIPAM) and the other on poly(N-isopropylmethacrylamide) (PNIPMAM), to prepare bicomponent colloidal molecules, and show that the difference in VPTT between the two allows for induction of attractive interparticle interactions between the PNIPAM interaction sites at temperatures in between the two VPTTs, analogous to the interactions among patchy biomacromolecules such as many proteins.
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Affiliation(s)
| | | | | | | | | | | | - Peter Schurtenberger
- NanoLund , SE-22100 Lund , Sweden.,Lund Institute of advanced Neutron and X-ray Science (LINXS) , Lund University , SE-22370 Lund , Sweden
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10
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Carlström G, Elvander F, Swärd J, Jakobsson A, Akke M. Rapid NMR Relaxation Measurements Using Optimal Nonuniform Sampling of Multidimensional Accordion Data Analyzed by a Sparse Reconstruction Method. J Phys Chem A 2019; 123:5718-5723. [PMID: 31194551 DOI: 10.1021/acs.jpca.9b04152] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Nonuniform sampling (NUS) of multidimensional NMR data offers significant time savings while improving spectral resolution or increasing sensitivity per unit time. However, NUS has not been widely used for quantitative analysis because of the nonlinearity of most methods used to model NUS data, which leads to problems in estimating signal intensities, relaxation rate constants, and their error bounds. Here, we present an approach that avoids these limitations by combining accordion spectroscopy and NUS in the indirect dimensions of multidimensional spectra and then applying sparse exponential mode analysis, which is well suited for analyzing accordion-type relaxation data in a NUS context. By evaluating the Cramér-Rao lower bound of the variances of the estimated relaxation rate constants, we achieve a robust benchmark for the underlying reconstruction model. Furthermore, we design NUS schemes optimized with respect to the information theoretical lower bound of the error in the parameters of interest, given a specified number of sampling points. The accordion-NUS method compares favorably with conventional relaxation experiments in that it produces identical results, within error, while shortening the length of the experiment by an order of magnitude. Thus, our approach enables rapid acquisition of NMR relaxation data for optimized use of spectrometer time or accurate measurements on samples of limited lifetime.
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Affiliation(s)
| | - Filip Elvander
- Department of Mathematical Statistics , Lund University , Box 118, SE-22100 Lund , Sweden
| | - Johan Swärd
- Department of Mathematical Statistics , Lund University , Box 118, SE-22100 Lund , Sweden
| | - Andreas Jakobsson
- Department of Mathematical Statistics , Lund University , Box 118, SE-22100 Lund , Sweden
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11
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Nilsson EJ, Huber M, Carlström G, Söderman O, Bowron DT, Edler KJ, Alfredsson V. Stability and behaviour in aqueous solutions of the anionic cubic silsesquioxane substituted with tetramethylammonium. Phys Chem Chem Phys 2019; 21:6732-6742. [PMID: 30860209 DOI: 10.1039/c8cp05682j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The aqueous behaviour of the anionic octa-tetramethylammonium substituted cubic silsesquioxane, [N(CH3)4]8[Si8O20], was studied with quantitative 29Si-NMR. This molecule partially fragments in aqueous solutions, forming several smaller entities. The most abundant silica species are the monomer, dimer, cyclic trimer, cyclic tetramer and double three-ring. Higher concentrations are required in order to prevent complete fragmentation of the cubic structure. Additives such as alcohols and tetraalkylammonium salts have a stabilising effect on the cubic silsesquioxane, unlike sodium salts that destabilise it. A high concentration solution, containing the non-fragmented molecule as well as entities resulting from fragmentations, was investigated with neutron scattering coupled with modelling, using empirical potential structure refinement (EPSR). The modelling reveals that TMA+ ions coordinates to all different silica species, with approximately three TMA+ per cube. These are located at the faces of the cube.
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Affiliation(s)
- Emelie J Nilsson
- Physical Chemistry, KILU, Lund University, P.O. Box 124, SE-22100 Lund, Sweden.
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12
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Köhler C, Carlström G, Tångefjord S, Papavoine T, Lepistö M, Edman K, Akke M. Backbone 1H, 13C, and 15N resonance assignments of the ligand binding domain of the human wildtype glucocorticoid receptor and the F602S mutant variant. Biomol NMR Assign 2018; 12:263-268. [PMID: 29667121 PMCID: PMC6132842 DOI: 10.1007/s12104-018-9820-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 03/31/2018] [Indexed: 05/16/2023]
Abstract
The glucocorticoid receptor (GR) is a nuclear hormone receptor that regulates key genes controlling development, metabolism, and the immune response. GR agonists are efficacious for treatment of inflammatory, allergic, and immunological disorders. Steroid hormone binding to the ligand-binding domain (LBD) of GR is known to change the structural and dynamical properties of the receptor, which in turn control its interactions with DNA and various co-regulators and drive the pharmacological response. Previous biophysical studies of the GR LBD have required the use of mutant forms to overcome issues with limited protein stability and high aggregation propensity. However, these mutant variants are known to also influence the functional response of the receptor. Here we report a successful protocol for protein expression, purification, and NMR characterization of the wildtype human GR LBD. We achieved chemical shift assignments for 90% of the LBD backbone resonances, with 216 out of 240 non-proline residues assigned in the 1H-15N TROSY spectrum. These advancements form the basis for future investigations of allosteric effects in GR signaling.
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Affiliation(s)
- Christian Köhler
- Respiratory, Inflammation and Autoimmunity, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Göran Carlström
- Centre for Analysis and Synthesis, Department of Chemistry, Lund University, Lund, Sweden
| | - Stefan Tångefjord
- Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Tineke Papavoine
- Respiratory, Inflammation and Autoimmunity, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Matti Lepistö
- Respiratory, Inflammation and Autoimmunity, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - Karl Edman
- Discovery Sciences, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden.
| | - Mikael Akke
- Biophysical Chemistry, Center for Molecular Protein Science, Department of Chemistry, Lund University, Lund, Sweden.
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Mendes Ferreira T, Sood R, Bärenwald R, Carlström G, Topgaard D, Saalwächter K, Kinnunen PKJ, Ollila OHS. Acyl Chain Disorder and Azelaoyl Orientation in Lipid Membranes Containing Oxidized Lipids. Langmuir 2016; 32:6524-33. [PMID: 27260273 DOI: 10.1021/acs.langmuir.6b00788] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Oxidized phospholipids occur naturally in conditions of oxidative stress and have been suggested to play an important role in a number of pathological conditions due to their effects on a lipid membrane acyl chain orientation, ordering, and permeability. Here we investigate the effect of the oxidized phospholipid 1-palmitoyl-2-azelaoyl-sn-glycero-3-phosphocholine (PazePC) on a model membrane of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) using a combination of (13)C-(1)H dipolar-recoupling nuclear magnetic resonance (NMR) experiments and united-atom molecular dynamics (MD) simulations. The obtained experimental order parameter SCH profiles show that the presence of 30 mol % PazePC in the bilayer significantly increases the gauche content of the POPC acyl chains, therefore decreasing the thickness of the bilayer, although with no stable bilayer pore formation. The MD simulations reproduce the disordering effect and indicate that the orientation of the azelaoyl chain is highly dependent on its protonation state with acyl chain reversal for fully deprotonated states and a parallel orientation along the interfacial plane for fully protonated states, deprotonated and protonated azelaoyl chains having negative and positive SCH profiles, respectively. Only fully or nearly fully protonated azelaoyl chain are observed in the (13)C-(1)H dipolar-recoupling NMR experiments. The experiments show positive SCH values for the azelaoyl segments confirming for the first time that oxidized chains with polar termini adopt a parallel orientation to the bilayer plane as predicted in MD simulations.
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Affiliation(s)
- Tiago Mendes Ferreira
- Institut für Physik - NMR, Martin-Luther-Universität Halle-Wittenberg , 06108 Halle, Germany
| | - Rohit Sood
- Department of Neuroscience and Biomedical Engineering, Aalto University , 02150 Espoo, Finland
| | - Ruth Bärenwald
- Institut für Physik - NMR, Martin-Luther-Universität Halle-Wittenberg , 06108 Halle, Germany
| | - Göran Carlström
- Centre for Analysis and Synthesis, Lund University , SE-221 00 Lund, Sweden
| | - Daniel Topgaard
- Physical Chemistry, Lund University , SE-221 00 Lund, Sweden
| | - Kay Saalwächter
- Institut für Physik - NMR, Martin-Luther-Universität Halle-Wittenberg , 06108 Halle, Germany
| | - Paavo K J Kinnunen
- Department of Neuroscience and Biomedical Engineering, Aalto University , 02150 Espoo, Finland
| | - O H Samuli Ollila
- Department of Neuroscience and Biomedical Engineering, Aalto University , 02150 Espoo, Finland
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Jarenmark M, Carlström G, Fredin LA, Hedberg Wallenstein J, Doverbratt I, Abrahamsson M, Persson P. Diastereomerization Dynamics of a Bistridentate RuII Complex. Inorg Chem 2016; 55:3015-22. [DOI: 10.1021/acs.inorgchem.5b02893] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | - Joachim Hedberg Wallenstein
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-41296 Gothenburg, Sweden
| | | | - Maria Abrahamsson
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-41296 Gothenburg, Sweden
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Ingimarsson S, Cantell K, Carlström G, Dalton B, Paucker K, Strander H. Immune reactions and long-term therapy with human leukocyte interferon. Acta Med Scand 2009; 209:17-19. [PMID: 6163328 DOI: 10.1111/j.0954-6820.1981.tb11545.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Twenty patients with osteosarcoma were treated with exogenous human leukocyte interferon for periods ranging from 6 to 18 months. Eleven of them remained free from detectable tumour growth during this treatment. Blood samples from all patients were tested for antibodies against interferon and against impurities in the interferon preparations. No patient developed detectable levels of neutralizing antibodies against interferon. All patients formed antibodies against contaminants in the concentrated crude interferon and the partially purified interferon preparation which had been used for treatment.
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16
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Kragelund BB, Hauenschild A, Carlström G, Pongs O, Finn BE. 1H, 13C, and 15N assignments of un-myristoylated Ca2+-frequenin, a synaptic efficacy modulator. J Biomol NMR 2000; 16:85-86. [PMID: 10718617 DOI: 10.1023/a:1008383002568] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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17
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Abstract
Calcium activation of the C-terminal domain of calmodulin was studied using 1H and 15N NMR spectroscopy. The important role played by the conserved bidentate glutamate Ca2+ ligand in the binding loops is emphasized by the striking effects resulting from a mutation of this glutamic acid to a glutamine, i.e. E104Q in loop III and E140Q in loop IV. The study involves determination of Ca2+ binding constants, assignments, and structural characterizations of the apo, (Ca2+)1, and (Ca2+)2 states of the E104Q mutant and comparisons to the wild-type protein and the E140Q mutant [Evenäs et al. (1997) Biochemistry 36, 3448-3457]. NMR titration data show sequential Ca2+ binding in the E104Q mutant. The first Ca2+ binds to loop IV and the second to loop III, which is the order reverse to that observed for the E140Q mutant. In both mutants, the major structural changes occur upon Ca2+ binding to loop IV, which implies a different response to Ca2+ binding in the N- and C-terminal EF-hands. Spectral characteristics show that the (Ca2+)1 and (Ca2+)2 states of the E104Q mutant undergo global exchange on a 10-100 micros time scale between conformations seemingly similar to the closed and open structures of this domain in wild-type calmodulin, paralleling earlier observations for the (Ca2+)2 state of the E140Q mutant, indicating that both glutamic acid residues, E104 and E140, are required for stabilization of the open conformation in the (Ca2+)2 state. To verify that the NOE constraints cannot be fulfilled in a single structure, solution structures of the (Ca2+)2 state of the E104Q mutant are calculated. Within the ensemble of structures the precision is good. However, the clearly dynamic nature of the state, a large number of violated distance restraints, ill-defined secondary structural elements, and comparisons to the structures of calmodulin indicate that the ensemble does not provide a good picture of the (Ca2+)2 state of the E104Q mutant but rather represents the distance-averaged structure of at least two distinct different conformations.
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Affiliation(s)
- J Evenäs
- Physical Chemistry 2, Lund University, Sweden.
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18
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Abstract
The hydration of the d(CGCGAATTCGCG) B-DNA duplex in solution was studied by nuclear magnetic relaxation dispersion (NMRD) of the water nuclei 1H, 2H, and 17O, and by nuclear Overhauser effects (NOEs) in high-resolution two-dimensional 1H NMR spectra. By comparing results from the free duplex with those from its complex with netropsin, water molecules in the "spine of hydration" in the AATT region of the minor groove could be distinguished from hydration water elsewhere in the duplex. The 2H and 17O relaxation dispersions yield a model-independent residence time of 0.9(+/-0.1) ns at 4 degrees C for five highly ordered water molecules in the spine. When corrected for frequency offset effects, the NOE data yield the same residence time as the NMRD data, giving credence to both methods. At 27 degrees C, the residence time is estimated to 0.2 ns, a factor of 40 shorter than the tumbling time of the duplex. The NMRD data show that all water molecules associated with the duplex, except the five molecules in the spine, have residence times significantly shorter than 1 ns at 4 degrees C. There is thus no long-lived hydration structure associated with the phosphate backbone. In contrast to 2H and 17O, the 1H relaxation dispersion is dominated by labile DNA protons and therefore provides little information about DNA hydration.
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Affiliation(s)
- V P Denisov
- Condensed Matter Magnetic Resonance Group, Lund University, Sweden
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19
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Evenäs J, Thulin E, Malmendal A, Forsén S, Carlström G. NMR studies of the E140Q mutant of the carboxy-terminal domain of calmodulin reveal global conformational exchange in the Ca2+-saturated state. Biochemistry 1997; 36:3448-57. [PMID: 9131994 DOI: 10.1021/bi9628275] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
In the present investigation, the Ca2+ activation of the C-terminal domain of bovine calmodulin and the effects of replacing the bidentate Ca2+-coordinating glutamic acid residue in the 12th and last position of loop IV with a glutamine are studied by NMR spectroscopy. The mutation E140Q results in sequential Ca2+ binding in this domain and has far-reaching effects on the structure of (Ca2+)2 TR2C, thereby providing further evidence for the critical role of this glutamic acid residue for the Ca2+-induced conformational change of regulatory EF-hand proteins. Analyses of the NOESY spectra of the mutant under Ca2+-saturated conditions, such that 97% of the protein is in the (Ca2+)2 form, revealed two sets of mutually exclusive NOEs. One set of NOEs is found to be consistent with the closed structure observed in the apo state of the C-terminal domain of the wild-type protein, while the other set supports the open structure observed in the Ca2+-saturated state. In addition, several residues in the hydrophobic core exhibit broadened resonances. We conclude that the (Ca2+)2 form of the mutant experiences a global conformational exchange between states similar to the closed and open conformations of the C-terminal domain of wild-type calmodulin. A population of 65 +/- 15% of the open conformation and an exchange rate of (1-7) x 10(4) s(-1) were estimated from the NMR data and the chemical shifts of the wild-type protein. From a Ca2+ titration of the 15N-labeled mutant, the macroscopic binding constants [log(K1) = 4.9 +/- 0.3 and log(K2) = 3.15 +/- 0.10] and the inherent chemical shifts of the intermediate (Ca2+)1 form of the mutant were determined using NMR. Valuable information was also provided on the mechanism of the Ca2+ activation and the roles of the structural elements in the two Ca2+-binding events. Comparison with the wild-type protein indicates that the (Ca2+)1 conformation of the mutant is essentially closed but that some rearrangement of the empty loop IV toward the Ca2+-bound form has occurred.
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Affiliation(s)
- J Evenäs
- Center for Chemistry and Chemical Engineering, Lund University, Sweden
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20
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Potts BC, Carlström G, Okazaki K, Hidaka H, Chazin WJ. 1H NMR assignments of apo calcyclin and comparative structural analysis with calbindin D9k and S100 beta. Protein Sci 1996; 5:2162-74. [PMID: 8931135 PMCID: PMC2143283 DOI: 10.1002/pro.5560051103] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The homodimeric S100 protein calcyclin has been studied in the apo state by two-dimensional 1H NMR spectroscopy. Using a combination of scalar correlation and NOE experiments, sequence-specific 1H NMR assignments were obtained for all but one backbone and > 90% of the side-chain resonances. To our knowledge, the 2 x 90 residue (20 kDa) calcyclin dimer is the largest protein system for which such complete assignments have been made by purely homonuclear methods. Sequential and medium-range NOEs and slowly exchanging backbone amide protons identified directly the four helices and the short antiparallel beta-type interaction between the two binding loops that comprise each subunit of the dimer. Further analysis of NOEs enabled the unambiguous assignment of 556 intrasubunit distance constraints, 24 intrasubunit hydrogen bonding constraints, and 2 x 26 intersubunit distance constraints. The conformation of the monomer subunit was refined by distance geometry and restrained molecular dynamics calculations using the intrasubunit constraints only. Calculation of the dimer structure starting from this conformational ensemble has been reported elsewhere. The extent of structural homology among the apo calcyclin subunit, the monomer subunit of apo S100 beta, and monomeric apo calbindin D9k has been examined in detail by comparing 1H NMR chemical shifts and secondary structures. This analysis was extended to a comprehensive comparison of the three-dimensional structures of the calcyclin monomer subunit and calbindin D9k, which revealed greater similarity in the packing of their hydrophobic cores than was anticipated previously. Together, these results support the hypothesis that all members of the S100 family have similar core structures and similar modes of dimerization. Analysis of the amphiphilicity of Helix IV is used to explain why calbindin D9k is monomeric, but full-length S100 proteins form homodimers.
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Affiliation(s)
- B C Potts
- Department of Molecular Biology, Scripps Research Institute, La Jolla, California 92037, USA
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21
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Carlström G, Chazin WJ. Sequence dependence and direct measurement of crossover isomer distribution in model Holliday junctions using NMR spectroscopy. Biochemistry 1996; 35:3534-44. [PMID: 8639504 DOI: 10.1021/bi952571n] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A 32-base-pair model of the Holliday junction (HJ) intermediate in genetic recombination has been prepared and analyzed in-depth by 2D and 3D (1)H NMR spectroscopy. This HJ (J2P1) corresponds to a cyclic permutation of the base pairs at the junction relative to a previously studied HJ [J2; Chen, S.-M., & Chazin, W.J. (1994) Biochemistry 33, 11453-11459], designed to probe the effect of the sequence at the n - 1 position (where n is the residue directly at the branch point) on the stacking geometry. Observation of several interbase nuclear Overhauser effects (NOEs) clearly indicates a strong preference for the isomer opposite that observed for J2, confirming the dependence of stacking isomer preference on the sequence at the junction. As for other model HJs studied, a small equilibrium distribution of the alternate isomer could be identified. A sample of J2P1 was prepared with a single (15)N-labeled thymine residue at the branch point. 1D (15)n-filtered (1)H-detected experiments on this sample at low temperature give strong support for the co-existence of the two stacking isomers and provide a much more direct and accurate measure of the crossover isomer distribution. The comparative analysis of our immobile HJs and a model cruciform structure [Pikkemaat, J.A., van den Elst, H., van Boom, J.H., & Altona, C. (1994) Biochemistry 33, 14896-14907] sheds new light on the issue of the relevance of crossover isomer preference in vivo.
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Affiliation(s)
- G Carlström
- Department of Molecular Biology, Scripps Research Institute, La Jolla, California 92037, USA
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22
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Affiliation(s)
- G Carlström
- Department of Physical Chemistry, Lund University, Sweden
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Carlström G, Chazin WJ. Two-dimensional 1H nuclear magnetic resonance studies of the half-saturated (Ca2+)1 state of calbindin D9k. Further implications for the molecular basis of cooperative Ca2+ binding. J Mol Biol 1993; 231:415-30. [PMID: 8389885 DOI: 10.1006/jmbi.1993.1291] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Calbindin D9k exhibits cooperative binding of two calcium ions, hence study of the half-saturated states of the protein is critical to understanding the binding process. However, the half-saturated states are not significantly populated under equilibrium conditions. To circumvent this problem, an absolutely conserved glutamic acid residue in the C-terminal binding site (site II) has been mutated to glutamine (E65Q), causing a substantial reduction in calcium affinity and permitting detailed two-dimensional 1H NMR analysis of calbindin D9k with a calcium ion bound only in the N-terminal EF-hand. Complete 1H resonance assignments have been obtained for (Ca2+)1 E65Q, as well as near complete assignments for the apo and (Ca2+)2 states. A value of 1.1(+/- 0.2) x 10(3) M-1 has been determined for the calcium binding constant in site II, from an analysis of the chemical shift changes in response to titration with calcium. The elements of secondary structure and global folding patterns were identified from nuclear Overhauser effects, backbone spin-spin coupling constants and the exchange rates of backbone amide protons. Although the mutation has only very small effects on the secondary structure and global fold of the protein, it so drastically lowers affinity for Ca2+ in the C-terminal site that (Ca2+)2 E65Q does not correspond to a standard (Ca2+)2 state. From the analysis of the half-saturated state, it is apparent that some reorganization of the structure and changes in the internal dynamics of calbindin D9k does occur for each step of the apo-->(Ca2+)1(I)-->(Ca2+)2 binding pathway. When the first ion is bound to the N-terminal EF-hand, that half of the molecule adopts a conformation and dynamic state similar to the fully calcium-loaded protein state, whereas only minor changes occur in the C-terminal EF-hand. It is only upon binding of the second calcium ion that the C-terminal EF-hand switches over to the fully calcium-loaded state. Together with the results from our earlier study of the apo-->(Ca2+)1(II)-->(Ca2+)2 binding pathway, these findings indicate that changes in protein conformation and dynamics associated with Ca2+ binding contribute to the observed positive cooperativity, and that the molecular details of the cooperative binding events are different for the two binding pathways.
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Affiliation(s)
- G Carlström
- Department of Molecular Biology, Scripps Research Institute, La Jolla, CA 92037
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24
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Carlström G, Halle B. The state of water in non-ionic surfactant solutions and lyotropic phases. Oxygen-17 magnetic relaxation study. ACTA ACUST UNITED AC 1989. [DOI: 10.1039/f19898501049] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Söderman O, Carlström G, Olsson U, Wong TC. Nuclear magnetic resonance relaxation in micelles. Deuterium relaxation at three field strengths of three positions on the alkyl chain of sodium dodecyl sulphate. ACTA ACUST UNITED AC 1988. [DOI: 10.1039/f19888404475] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
One hundred and forty-one seven-year-old Swedish children took part in an extensive neuropsychiatric study involving total population samples of children who had shown perceptual, motor and attentional deficits in pre-school, and blindly examined comparison children. The present paper reports on generalized hyperkinesis, i.e. hyperactivity in the child in all of three different assessment settings. About a third of children diagnosed according to strict criteria as suffering from 'Minimal Brain Dysfunction' showed generalized hyperkinesis. In children without perceptual-motor deficits, hyperkinesis was very much rarer. A total population frequency for generalized hyperkinesis in the range of 1-3% is reported as probable. Heredity for delayed maturation, non-optimal pre-, peri- and neonatal factors and adverse psychosocial factors were found to interact in the shaping of the disorder.
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Gillberg C, Svenson B, Carlström G, Waldenström E, Rasmussen P. Mental retardation in Swedish urban children: some epidemiological considerations. Appl Res Ment Retard 1983; 4:207-18. [PMID: 6660864 DOI: 10.1016/s0270-3092(83)80002-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The total population of children born in 1971 and living in Gothenburg, Sweden, by the end of 1977 was screened in order to estimate prevalence figures for various neurodevelopmental disorders. Ninety-four percent of all children assessed attended public preschools. Questionnaires aimed at detecting perceptual, conceptual, motor, and attentional deficits were completed by preschool teachers for 72% of children in these schools. Samples of children with and without problems on the questionnaire were given neuropsychiatric examinations. National registers were searched to identify mentally retarded children not in public preschools. The total population frequency figure for unequivocal mental retardation was almost 1% with an additional 1% of the total population deemed to be of borderline intelligence.
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Gillberg C, Carlström G, Rasmussen P, Waldenström E. Perceptual, motor and attentional deficits in seven-year-old children. Neurological screening aspects. Acta Paediatr Scand 1983; 72:119-24. [PMID: 6858674 DOI: 10.1111/j.1651-2227.1983.tb09675.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In an extensive neuropsychiatric study of seven-year-old children, operational criteria for diagnosing minimal brain dysfunction (MBD) syndrome were used. Detailed behavioural assessment and meticulous neurological examination provided the basis for the MBD diagnosis. The time-consuming specialist examination by the child neurologist was considered too sophisticated for use in everyday clinical practice. Therefore, the results obtained at a short neurodevelopmental screening assessment performed by a child psychiatrist were analysed with the aim of finding a limited set of neurological examination items with high discriminating capacity detecting for MBD syndromes. A set of six such items (diadochokinesis, hopping on one leg, standing on one leg, cutting out a paper circle, associated movements when walking on lateral sides of feet and the labyrinth test of the WISC) produced a minimal rate of misclassified cases. It is argued that this discriminant set may be useful in everyday child psychiatric and pediatric assessment of children who raise suspicion of suffering from MBD.
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Gillberg C, Rasmussen P, Carlström G, Svenson B, Waldenström E. Perceptual, motor and attentional deficits in six-year-old children. Epidemiological aspects. J Child Psychol Psychiatry 1982; 23:131-44. [PMID: 7082448 DOI: 10.1111/j.1469-7610.1982.tb00058.x] [Citation(s) in RCA: 146] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A total population study of 4797 six-year-old children attending the public preschools in the city of Göteborg (Gothenburg) has been carried out. A questionnaire with 34 questions about MBD-related problems was distributed to all pre-school teachers. Three thousand four hundred and forty-eight questionnaires were completed. Factor analysis of the questionnaire and empirical results from a pilot study provided the basis for selecting for further study children with pre-school signs and symptoms suggestive of MBD. Neurological, psychiatric and psychological assessment of 82 children with, and 59 children without, pre-school symptoms of MBD revealed that in the index groups 41% of the children, and in the control group 3% of the children, had MBD. Extrapolation procedures gave a total population frequency of 1.2% with severe MBD and a further 5.9% with mild-moderate MBD. A very large questionnaire refusal rate (28%) is discussed. The relevance of the calculated frequency figures, especially as regards the mild-moderate MBD category, cannot be properly evaluated until long-term follow-up has been completed.
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Gillberg C, Frisk M, Carlström G, Rasmussen P. "Complex reaction times" in so-called minimal brain dysfunction. Acta Paedopsychiatr 1981; 47:245-52. [PMID: 7036652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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33
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Ingimarsson S, Carlström G, Cantell K, Strander H. Virus infections and recurrence of osteosarcoma in patients receiving human leukocyte interferon. Int J Cancer 1980; 26:395-9. [PMID: 6166573 DOI: 10.1002/ijc.2910260402] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Human leukocyte interferon was given as adjuvant treatment for osteosarcoma in 26 patients. Blood from these patients was studied at regular intervals for antibodies to various micro-organisms. A continuous record of clinically manifest infections during the course of interferon therapy was made in 23 of the 26 patients. Distant metastases arose in 14 patients - the metastasis group. The report presents comparisons between these patients and the non-metastasis group. Seroconversion in tests with any of the studied micro-organisms was not common. Most of the seroconversions were not associated with clinical symptoms. Seroconversion during interferon therapy was confined to patients in the metastasis group. In some cases there was a chronologic link with early evidence of metastasis. The results of the serologic investigations are discussed and are correlated to the course of interferon therapy and of the neoplastic disease.
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34
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Evaldson G, Carlström G, Lagrelius A, Malmborg AS, Nord CE. Microbiological findings in pregnant women with premature rupture of the membranes. Med Microbiol Immunol 1980; 168:283-97. [PMID: 7442615 DOI: 10.1007/bf02121812] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
From 30 consecutive cases of premature rupture of the membranes (PROM) and matched controls, specimens from urine, cervix, amniotic fluid, and placenta as well as neonatal nose and throat swabs were investigated bacteriologically and virologically. In addition virus serological investigation was done. Among the PROM cases the anaerobic cervical isolates outnumbered the aerobic ones, and the total number of aerobic as well as anaerobic isolates was less in the control group. The anaerobes B. fragilis and Strept. intermedius were isolated from the cervix, amniotic fluid, or placenta in 23% and 30% of the PROM patients, respectively. None of the controls harboured B. fragilis, while Strept. intermedius was isolated from 6.7% of the controls. Group B streptococci were recovered from the mother's cervix in 20% of the PROM patients and in 6.7% among the controls. Four cases of neonatal septicaemia were encountered, and another two cases were clinically suspected, but not microbiologically verified, contributing to a high perinatal mortality rate (17,6%). Of the PROM patients, 27% developed puerperal infection, while none of the control mothers had such complications. The significance of the anaerobic bacteria as well as group B streptococci for the maternal and neonatal outcome in cases of PROM is discussed, and a possible aetiological role of ascending infection in this complication of pregnancy is postulated.
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Abstract
This report concerns a boy with congenital rubella virus infection. The diagnosis was confirmed by virus isolation, demonstration of rubella-specific serum IgM and by persistence of serum antibody at the age of 9 months. In 2 sera from the mother sampled 2 weeks apart 20 months before the birth of the boy, low titers of rubella antibody were demonstrated by hemagglutination-inhibition, hemolysis-in-gel and complement fixation tests, but not by neutralization. Significant rises in titer were demonstrable by all serologic reactions--including neutralization--at the time of birth of the infected child. The mother was not aware of any rubella-like illness or exposure to such disease during pregnancy. The case is discussed against findings of neutralizing activity in sera from natural immunes and rubella vaccinees.
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Abstract
Viral and bacterial infections in 20 children under 3 years of age were studied in a day centre for 12 weeks. Febrile illnesses were found on one occasion in each of 11 children but no serious infection occurred. Pneumococci types 6, 9, or 19 were isolated from all children but more often from those with rhinitis or cough. The individual child had an average of 2 viral infections. Adenovirus types 1, 2, 5, coxsackievirus type B5, herpes simplex virus or respiratory syncytial virus was isolated from 12% of the oropharynx swabs and 40% of the fecal specimens. When a virus was first isolated from the oropharynx, the children were asymptomatic or had only rhinitis in 73% of the cases which might indicate that the dismissing of symptomatic children is of limited value in controlling the spread of infections in a day care centre. Cytomegalovirus was recovered from 22% of the urine specimens. Carrier frequency of cytomegalovirus was 23% in 40 other children attending one of 13 different day care centers. Because asymptomatic cytomegalovirus infections apparently occur frequently among small children in Sweden, it seems reasonable not to take pronounced measures of isolating the children in the relatively few recognized cases of cytomegalovirus infections.
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Strander H, Cantell K, Carlström G, Ingimarsson S, Jakobsson P, Nilsonne U. Acute infections in interferon-treated patients with osteosarcoma: preliminary report of a comparative study. J Infect Dis 1976; 133 Suppl:A245-8. [PMID: 1064674 DOI: 10.1093/infdis/133.supplement_2.a245] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The incidence of acute infections in eight patients with osteosarcoma who are receiving interferon regularly is currently being compared with the incidence among their family members. Observations thus far indicate that the patients treated with interferon are less frequently and less severely ill than their untreated family contacts. The study is continuing, and the patients will also be observed after discontinuation of interferon treatment. Sera are regularly frozen for future viral serologic tests. The preliminary clinical data indicate that therapy with exogenous interferon may afford protection against common acute infections.
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Aho K, Strander H, Leikola J, Kleemola M, Carlström G, Cantell K. An inhibitor of the complement-fixation reaction associated with interferon treatment. Clin Immunol Immunopathol 1976; 5:399-406. [PMID: 1064495 DOI: 10.1016/0090-1229(76)90049-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Liberg P, Carlström G. Studies of transferrin polymorphism in Swedish cattle using agarose gel electrophoresis. Acta Vet Scand 1976; 17:451-7. [PMID: 1015477 PMCID: PMC8383962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The polymorphic transferrin picture in the sera from 894 Swedish cattle was investigated with an agarose gel electrophoresis technique. The serum transferrin bands in the electrophoresis pattern were first identified by labelling with 59Fe. Six existing phenotypes based on the alleles TfA, TfD and TfE could be detected. The frequencies of transferrin types and transferrin alleles are presented, and it is concluded that there are great differences in the frequencies between the Swedish Red and White and the Swedish Friesian.
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Carlström G, Liberg P. Agarose gel electrophoretic separation of blood serum proteins in cattle. Acta Vet Scand 1975; 16:520-4. [PMID: 1211329 PMCID: PMC8396014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The agarose gel electrophoresis described by Johansson (1972) was modified so that a buffer of pH 7.9 was used in the gel, whereas the buffer in the electrode vessels had a pH of 8.6. The cattle blood serum protein picture is described in detail. The β1-globulin zone shows a very distinct picture of the genetically polymorphic bovine transferrins. The region between the α- and β-globulins shows a number of faint and often very distinct bands. A faint background staining over the whole electrophoretogram may partly be caused by a rather strong lipoprotein in the α1-region, lipids thus having migrated all over the electrophoretogram. The modified method described is well suited as a “screen electrophoresis” for cattle serum and is also useful e.g. in studying bovine transferrin polymorphism.
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Strander H, Cantell K, Carlström G, Jakobsson PA. Clinical and laboratory investigations on man: systemic administration of potent interferon to man. J Natl Cancer Inst 1973; 51:733-42. [PMID: 4355215 DOI: 10.1093/jnci/51.3.733] [Citation(s) in RCA: 151] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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Carlström G. [Virus infections and toxoplasmosis during pregnancy]. Lakartidningen 1972; 69:Suppl 2:63-8. [PMID: 4645698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Carlström G. Studies on parturient paresis in dairy cows. V. On the composition and calcium binding capacity of two bovine serum protein fractions, with special regard to parturient paresis. Acta Vet Scand 1970; 11:89-102. [PMID: 5463871 PMCID: PMC8561598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
In healthy cows unaffected by imminent or recent calving the protein in serum can directly bind the overwhelming proportion of the bound calcium. In recent calvers this capacity is considerably less. When adding ammonium sulphate to blood serum to 62 % of total saturation a protein fraction precipitates which is mainly albumin. This fraction has a far greater calcium binding capacity than the soluble fraction, which contains most of the serum globulin, and the lowering of this capacity after calving is entirely referable to the former fraction. No difference has been found in these respects between normal cows after calving and cows with parturient paresis. An analysis of 10 amino acids in the two protein fractions described above showed that the amino acid composition of both exhibits differences between recent calvers and cows outside the calving period, and likewise that each of the two fractions differs in composition between healthy cows after calving and cows with parturient paresis.
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Baechler C, Bell ET, Borth R, Brody S, Carlström G, Kerr MG, Menzi A. Comparison of two immunochemical and three biological methods for the assay of human chorionic gonadotrophin in serum. Acta Endocrinol (Copenh) 1969; 61:117-32. [PMID: 5819071 DOI: 10.1530/acta.0.0610117] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Carlström G, Belfrage S, Ohlsson NM, Swedberg J. Cytomegalovirus infection complicating open-heart surgery. Scand J Thorac Cardiovasc Surg 1968; 2:57-62. [PMID: 4302472 DOI: 10.3109/14017436809131882] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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