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Zobel CM, Kuhn H, Schreiner M, Wenzel W, Wendtland J, Goekeri C, Scheit L, Oltmanns K, Rauschning D, Grossegesse M, Hofmann N, Wirtz H, Spethmann S. Impact of ACE I gene insertion/deletion, A-240T polymorphisms and the renin-angiotensin-aldosterone system on COVID-19 disease. Virol J 2024; 21:15. [PMID: 38200555 PMCID: PMC10782794 DOI: 10.1186/s12985-023-02283-w] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 12/30/2023] [Indexed: 01/12/2024] Open
Abstract
BACKGROUND The coronavirus disease 2019 (COVID-19) pandemic is driven by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, which has led to an enormous burden on patient morbidity and mortality. The renin-angiotensin-aldosterone system (RAAS) plays a significant role in various pulmonary diseases. Since SARS-CoV-2 utilizes the angiotensin-converting enzyme (ACE)2 receptor to exert its virulence and pathogenicity, the RAAS is of particular importance in COVID 19. METHODS Our preliminary study investigates retrospectively the influence of selected ACE-polymorphisms (I/D location at intron 16 in the B-coding sequence (rs4646994) and A-240T (rs 4291) at the A-promoter) as well as ACE1 and ACE2 serum levels on disease severity and the inflammatory response in inpatients and outpatients with COVID-19. RESULTS Our study included 96 outpatients and 88 inpatients (65.9% male, mean age 60 years) with COVID-19 from April to December 2020 in four locations in Germany. Of the hospitalized patients, 88.6% participants were moderately ill (n = 78, 64% male, median age 60 years), and 11.4% participants were severely ill or deceased (n = 10, 90% male, median age 71 years). We found no polymorphism-related difference in disease, in age distribution, time to hospitalization and time of hospitalization for the inpatient group. ACE1 serum levels were significantly increased in the DD compared to the II polymorphism and in the TT compared to the AA polymorphism. There was no significant difference in ACE 1 serum levels l between moderately ill and severely ill patients. However, participants requiring oxygen supplementation had significantly elevated ACE1 levels compared to participants not requiring oxygen, with no difference in ACE2 levels whereas females had significantly higher ACE2 levels. CONCLUSIONS Although there were no differences in the distribution of ACE polymorphisms in disease severity, we found increased proinflammatory regulation of the RAAS in patients with oxygen demand and increased serum ACE2 levels in women, indicating a possible enhanced anti-inflammatory immune response. CLINICAL TRIAL REGISTRATION PreBiSeCov: German Clinical Trials Register, DRKS-ID: DRKS00021591, Registered on 27th April 2020.
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Affiliation(s)
- Christian M Zobel
- Department of Internal Medicine, Bundeswehr Hospital Berlin, Scharnhorstrstr. 13, 10115, Berlin, Germany.
| | - Hartmut Kuhn
- Department of Respiratory Medicine, University of Leipzig, Leipzig, Germany
| | - Maximilian Schreiner
- Department of Internal Medicine, Bundeswehr Hospital Berlin, Scharnhorstrstr. 13, 10115, Berlin, Germany
| | - Werner Wenzel
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Berlin, Berlin, Germany
| | - Jasper Wendtland
- Department of Internal Medicine, Bundeswehr Hospital Hamburg, Hamburg, Germany
| | - Cengiz Goekeri
- Department of Infectious Diseases and Respiratory Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany
- Faculty of Medicine, Cyprus International University, Nicosia, Cyprus
| | - Lorenz Scheit
- Department of Internal Medicine, Bundeswehr Hospital Hamburg, Hamburg, Germany
| | - Klaas Oltmanns
- Department of Internal Medicine, Bundeswehr Hospital Westerstede, Westerstede, Germany
| | - Dominic Rauschning
- Department of Internal Medicine, Bundeswehr Hospital Koblenz, Koblenz, Germany
| | - Marica Grossegesse
- Centre for Biological Threats and Special Pathogens, ZBS1, Robert Koch Institute, Highly Pathogenic Viruses, Berlin, Germany
| | - Natalie Hofmann
- Centre for Biological Threats and Special Pathogens, ZBS1, Robert Koch Institute, Highly Pathogenic Viruses, Berlin, Germany
| | - Hubert Wirtz
- Department of Respiratory Medicine, University of Leipzig, Leipzig, Germany
| | - Sebastian Spethmann
- Deutsches Herzzentrum der Charité Berlin, Berlin, Germany
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität Zu Berlin, Berlin, Germany
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Zobel CM, Wenzel W, Krüger JP, Baumgarten U, Wagelöhner T, Neumann N, Foroutan B, Müller R, Müller A, Rauschning D, Schüßler M, Scheit L, Weinreich F, Oltmanns K, Keidel F, Koch M, Spethmann S, Schreiner M. Serum interleukin-6, procalcitonin, and C-reactive protein at hospital admission can identify patients at low risk for severe COVID-19 progression. Front Microbiol 2023; 14:1256210. [PMID: 37937220 PMCID: PMC10626435 DOI: 10.3389/fmicb.2023.1256210] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [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: 07/10/2023] [Accepted: 10/09/2023] [Indexed: 11/09/2023] Open
Abstract
Background COVID-19 can show a variable course, from asymptomatic infections to acute respiratory failure and death. For efficient allocation of resources, patients should be stratified according to their risk for a severe course as early as possible. Methods 135 hospitalized patients with COVID-19 pneumonia at four German hospitals were prospectively included in this observational study. A standardized clinical laboratory profile was taken at hospital admission and a panel of serum markers with possible roles in the COVID-associated cytokine storm were also determined. 112 patients could be evaluated. The primary endpoint of ventilator requirement or death within 30 days of symptom onset was met by 13 patients. Results Serum elevations of interleukin-6 (IL-6), procalcitonin (PCT), and C-reactive protein (CRP) at hospital admission were each highly significantly (p < 0.001) associated with ventilator requirement/death within 30 days of symptom onset. With a sensitivity of 92% and a specificity of 65-67%, IL-6 ≥ 52.8 pg/ml, PCT ≥ 0.11 ng/ml, and CRP ≥ 71.1 mg/L were predictive of a severe course of COVID-19. Positive likelihood ratios were between 2.6-2.8 and negative likelihood ratios were between 0.11-0.13 for these three markers. Conclusion Negative likelihood ratios indicate that IL-6, PCT, and CRP at hospital admission can be used for identifying patients at low risk for severe COVID-19 progression.
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Affiliation(s)
| | - Werner Wenzel
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital, Berlin, Germany
| | - Jan Philipp Krüger
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital, Berlin, Germany
| | - Ulrich Baumgarten
- Department of Internal Medicine, Bundeswehr Hospital, Berlin, Germany
| | - Tobias Wagelöhner
- Department of Internal Medicine, Bundeswehr Hospital, Berlin, Germany
| | - Nino Neumann
- Department of Internal Medicine, Bundeswehr Hospital, Berlin, Germany
| | - Behruz Foroutan
- Department of Internal Medicine, Bundeswehr Hospital, Berlin, Germany
| | - Rico Müller
- Department of Laboratory Medicine, Bundeswehr Hospital, Berlin, Germany
| | - Annette Müller
- Department of Laboratory Medicine, Bundeswehr Hospital, Berlin, Germany
| | - Dominic Rauschning
- Department of Internal Medicine, Bundeswehr Central Hospital, Koblenz, Germany
| | - Meike Schüßler
- Department of Internal Medicine, Bundeswehr Central Hospital, Koblenz, Germany
| | - Lorenz Scheit
- Department of Internal Medicine, Bundeswehr Hospital, Hamburg, Germany
| | - Felix Weinreich
- Department of Internal Medicine, Bundeswehr Hospital, Hamburg, Germany
| | - Klaas Oltmanns
- Department of Internal Medicine, Bundeswehr Hospital, Westerstede, Germany
| | - Franziska Keidel
- Department of Internal Medicine, Bundeswehr Hospital, Westerstede, Germany
| | - Maria Koch
- Department of Internal Medicine, Bundeswehr Hospital, Westerstede, Germany
| | - Sebastian Spethmann
- Department of Cardiology, Angiology and Intensive Care Medicine|CCM, Deutsches Herzzentrum der Charité – Medical Heart Center of Charité and German Heart Institute Berlin, Berlin, Germany
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
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Pecinatto H, Rêgo CRC, Wenzel W, Frota CA, Perrone BMS, Piotrowski MJ, Guedes-Sobrinho D, Dias AC, Mota C, Gusmão MSS, Frota HO. Unveiling oxygen vacancy impact on lizardite thermo and mechanical properties. Sci Rep 2023; 13:17157. [PMID: 37821570 PMCID: PMC10567844 DOI: 10.1038/s41598-023-44424-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 10/08/2023] [Indexed: 10/13/2023] Open
Abstract
Here, we performed a systematic DFT study assisted by the workflow framework SimStack for the mechanical and thermodynamic properties of the clay mineral lizardite in pristine and six different types of O vacancies configurations. In most cases, the defect caused a structural phase transition in the lizardite from the trigonal (pristine) to the triclinic phase. The results show that oxygen vacancies in lizardite significantly reduce the lattice thermal conductivity, accompanied by an elastic moduli reduction and an anisotropy index increase. Through the P-V relation, an increase in compressibility was evidenced for vacancy configurations. Except for the vacancy with the same crystalline structure as pristine lizardite, the sound velocities of the other vacancy configurations produce a decrease in these velocities, and it is essential to highlight high values for the Grüneisen parameter. We emphasize the great relevance of the punctual-defects introduction, such as O vacancies, in lizardite, since this microstructural design is responsible for the decrease of the lattice thermal conductivity in comparison with the pristine system by decreasing the heat transfer ability, turning lizardite into a promising candidate for thermoelectric materials.
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Affiliation(s)
- H Pecinatto
- PPG-FIS, Federal University of Amazonas, Manaus, AM, Brazil
| | - Celso R C Rêgo
- Karlsruhe Institute of Technology (KIT), Institute of Nanotechnology Hermann-von-Helmholtz-Platz, 76344, Eggenstein-Leopoldshafen, Germany.
| | - W Wenzel
- Karlsruhe Institute of Technology (KIT), Institute of Nanotechnology Hermann-von-Helmholtz-Platz, 76344, Eggenstein-Leopoldshafen, Germany
| | - C A Frota
- Department of Civil Engineering, Federal University of Amazonas, Manaus, AM, Brazil
| | - B M S Perrone
- PPG-FIS, Federal University of Amazonas, Manaus, AM, Brazil
| | - Maurício J Piotrowski
- Department of Physics, Federal University of Pelotas, PO Box 354, Pelotas, RS, 96010-900, Brazil
| | | | - Alexandre C Dias
- University of Brasília, Institute of Physics, Brasília-DF, 70919-970, Brazil
| | - Cicero Mota
- Department of Mathematics, Federal University of Amazonas, Manaus, AM, Brazil
| | - M S S Gusmão
- Department of Physics, Federal University of Amazonas, Manaus, AM, Brazil
| | - H O Frota
- Department of Physics, Federal University of Amazonas, Manaus, AM, Brazil
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Nesic M, Vogel J, Krüger JP, Wenzel W, Sahebi A, Rassaf T, Siebermair J, Wesemann U. Association between different dimensions of anger and symptoms of post-traumatic stress disorder in at-risk cardiovascular patients during the COVID-19 pandemic. Front Psychiatry 2023; 14:1228192. [PMID: 37829760 PMCID: PMC10565353 DOI: 10.3389/fpsyt.2023.1228192] [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] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 09/07/2023] [Indexed: 10/14/2023] Open
Abstract
Introduction The common connecting factor between PTSD and cardiovascular diseases lies in the disruption of the stress processing system. The COVID-19 pandemic has led to an increase in stress levels worldwide. Due to the life-threatening situation of affected risk patients, this also led to the accumulation of post-traumatic stress symptoms (PTSS). The influence of anger on cardiovascular diseases has hardly been investigated so far. The focus of this study is on anger regulation in cardiovascular risk patients. The COVID-19 pandemic is considered as an additional stressor in this study, but not as a separate entity. The hypothesis is that individuals with inward anger are more prone to post-traumatic stress disorder (PTSD). Methods As part of the routine examination, all patients who were hospitalized between January 1st, 2021 and May 31st, 2022 with high-risk cardiovascular diseases were included. A total of N = 153 (84.1%) subjects participated in the study. On admission, anger (STAXI-2) and PTSD (PCL-5) were assessed using questionnaires. The relationship between different domains of anger and PTSS was examined. Results Inwardly directed anger was more pronounced in this population than in a standard sample (+1 SD) and had a significant impact on the presence of PTSD (B = -0.72, p < 0.001). Additionally, correlations were found between inward-directed anger and PTSD, as well as all other anger expressions studied and the PTSD total score. Discussion It can be assumed that anger and its regulation are relevant factors for both cardiac diseases and PTSD. The study results can be used for prevention, rehabilitation and therapeutic measures. However, the impact of inner anger on PTSD is theoretical and based on statistical testing. A confirmatory longitudinal study is needed to substantiate these results.
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Affiliation(s)
- Mihailo Nesic
- Department of Psychiatry, Psychotherapy and Psychotraumatology, Bundeswehr Hospital Berlin, Berlin, Germany
| | - Julia Vogel
- Department of Cardiology and Vascular Medicine, West German Heart and Vascular Center Essen, University Duisburg-Essen, Duisberg, Germany
| | | | - Werner Wenzel
- Department of Microbiology, Bundeswehr Hospital Berlin, Berlin, Germany
| | - Ali Sahebi
- Psychosocial Injuries Research Center, Ilam University of Medical Sciences, Ilam, Iran
- Non-Communicable Diseases Research Center, Ilam University of Medical Sciences, Ilam, Iran
| | - Tienush Rassaf
- Department of Cardiology and Vascular Medicine, West German Heart and Vascular Center Essen, University Duisburg-Essen, Duisberg, Germany
| | - Johannes Siebermair
- Department of Cardiology and Vascular Medicine, West German Heart and Vascular Center Essen, University Duisburg-Essen, Duisberg, Germany
- Department of Cardiology, Krankenhaus Göttlicher Heiland GmbH, Vienna, Austria
| | - Ulrich Wesemann
- Department of Psychiatry, Psychotherapy and Psychotraumatology, Bundeswehr Hospital Berlin, Berlin, Germany
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de Araujo LO, Rêgo CRC, Wenzel W, Silveira DN, Piotrowski MJ, Sabino FP, Pramudya Y, Guedes-Sobrinho D. How cation nature controls the bandgap and bulk Rashba splitting of halide perovskites. J Comput Chem 2023; 44:1395-1403. [PMID: 36805580 DOI: 10.1002/jcc.27094] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [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: 12/11/2022] [Revised: 02/03/2023] [Accepted: 02/08/2023] [Indexed: 02/23/2023]
Abstract
Because of instability issues presented by metal halide perovskites based on methylammonium (MA), its replacement to Cs $$ \mathrm{Cs} $$ has emerged as an alternative to improve the materials' durability. However, the impact of this replacement on electronic properties, especially gap energy and bulk Rashba splitting remains unclear since electrostatic interactions from organic cations can play a crucial role. Through first-principles calculations, we investigated how organic/inorganic cations impact the electronic properties of MAPbI 3 $$ {\mathrm{MAPbI}}_3 $$ and CsPbI 3 $$ {\mathrm{CsPbI}}_3 $$ perovskites. Although at high temperatures the organic cation can assume spherical-like configurations due to its rotation into the cages, our results provide a complete electronic mechanism to show, from a chemical perspective based on ab initio calculations at 0 K $$ 0\ \mathrm{K} $$ , how the MA $$ \mathrm{MA} $$ dipoles suppression can reduce the MAPbI 3 $$ {\mathrm{MAPbI}}_3 $$ gap energy by promoting a degeneracy breaking in the electronic states from the PbI 3 $$ {\mathrm{PbI}}_3 $$ framework, while the dipole moment reinforcement is crucial to align theory ↔ $$ \leftrightarrow $$ experiment, increasing the bulk Rashba splitting through higher Pb $$ \mathrm{Pb} $$ off-centering motifs. The lack of permanent dipole moment in Cs $$ \mathrm{Cs} $$ results in CsPbI 3 $$ {\mathrm{CsPbI}}_3 $$ polymorphs with a pronounced Pb $$ \mathrm{Pb} $$ on-centering-like feature, which causes suppression in their respective bulk Rashba effect.
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Affiliation(s)
| | - Celso R C Rêgo
- Institute of Nanotechnology Hermann-von-Helmholtz-Platz, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - W Wenzel
- Institute of Nanotechnology Hermann-von-Helmholtz-Platz, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Danilo N Silveira
- Department of Chemistry, Federal University of Paraná, Curitiba, Brazil
| | | | - Fernando P Sabino
- Center for Natural and Human Sciences, Federal University of ABC, Santo André, Brazil
| | - Yohanes Pramudya
- Institute of Nanotechnology Hermann-von-Helmholtz-Platz, Karlsruhe Institute of Technology, Karlsruhe, Germany
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Uttinger MJ, Hundschell CS, Lautenbach V, Pusara S, Bäther S, Heyn TR, Keppler JK, Wenzel W, Walter J, Kozlowska M, Wagemans AM, Peukert W. Determination of specific and non-specific protein-protein interactions for beta-lactoglobulin by analytical ultracentrifugation and membrane osmometry experiments. Soft Matter 2022; 18:6739-6756. [PMID: 36040122 DOI: 10.1039/d2sm00908k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Protein-protein interactions are essential for the understanding of biological processes. Specific protein aggregation is an important aspect for many biological systems. In particular, electrostatic interactions play the key role for protein-protein interactions, as many amino acids have pH-dependent charge states. Moreover, protein dissociation is directly related to the solution pH, ionic strength, temperature and protein concentration. The subtle interplay between different specific and non-specific interactions is demonstrated for beta-lactoglobulin (BLG) with a focus on low salt concentrations, thus mimicking technically relevant processing conditions. BLG is a well-characterized model system, proven to attain its monomer-dimer equilibrium strongly dependent upon the pH of the solution. In this manuscript, we present a unique combination of analytical ultracentrifugation and membrane osmometry experiments, which quantifies specific and non-specific interactions, i.e. in terms of the dimer dissociation constants and the second osmotic virial coefficient, at pH 3 and 7 and sodium chloride concentrations of 10 mM and 100 mM. This provides direct insight to protein-protein interactions for a system with a concentration-dependent monomer-dimer equilibrium. Moreover, using a coarse-grained extended DLVO model in combination with molecular dynamics simulations, we quantify non-specific monomer-monomer, monomer-dimer and dimer-dimer interactions as well as the binding free energy of BLG dimerization from theoretical calculations. The experimentally determined interactions are shown to be mainly governed by electrostatic interactions and further agree with free energy calculations. Our experimental protocol aims to determine non-specific and specific interactions for a dynamically interacting system and provides an understanding of protein-protein interactions for BLG at low salt concentrations.
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Affiliation(s)
- M J Uttinger
- Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems, Friedrich-Alexander-Universität Erlangen-Nürnberg, Haberstraße 9a, 91058 Erlangen, Germany.
| | - C S Hundschell
- Institute of Food Technology and Food Chemistry, Department of Food Colloids, Technical University Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - V Lautenbach
- Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems, Friedrich-Alexander-Universität Erlangen-Nürnberg, Haberstraße 9a, 91058 Erlangen, Germany.
| | - S Pusara
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - S Bäther
- Institute of Food Technology and Food Chemistry, Department of Food Colloids, Technical University Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - T R Heyn
- Institute of Human Nutrition and Food Science, Division of Food Technology, Kiel University, 24118 Kiel, Germany
| | - J K Keppler
- Laboratory of Food Process Engineering, Wageningen University, Wageningen, The Netherlands
| | - W Wenzel
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - J Walter
- Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems, Friedrich-Alexander-Universität Erlangen-Nürnberg, Haberstraße 9a, 91058 Erlangen, Germany.
| | - M Kozlowska
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - A M Wagemans
- Institute of Food Technology and Food Chemistry, Department of Food Colloids, Technical University Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - W Peukert
- Institute of Particle Technology, Interdisciplinary Center for Functional Particle Systems, Friedrich-Alexander-Universität Erlangen-Nürnberg, Haberstraße 9a, 91058 Erlangen, Germany.
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Yamin P, Hubbuch J, Wenzel W. Modeling Protein Solubility. CHEM-ING-TECH 2018. [DOI: 10.1002/cite.201855440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- P. Yamin
- Karlsruher Institut für Technologie; Institut für Nanotechnologie; Kaiserstraße 12 76021 Karlsruhe Deutschland
| | - J. Hubbuch
- Karlsruher Institut für Technologie; Institut für Bio- und Lebensmitteltechnik; Kaiserstraße 12 76021 Karlsruhe Deutschland
| | - W. Wenzel
- Karlsruher Institut für Technologie; Institut für Nanotechnologie; Kaiserstraße 12 76021 Karlsruhe Deutschland
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Frickmann H, Köller T, Hagen RM, Ebert KP, Müller M, Wenzel W, Gatzer R, Schotte U, Binder A, Skusa R, Warnke P, Podbielski A, Rückert C, Kreikemeyer B. Molecular Epidemiology of Multidrug-Resistant Bacteria Isolated from Libyan and Syrian Patients with War Injuries in Two Bundeswehr Hospitals in Germany. Eur J Microbiol Immunol (Bp) 2018; 8:1-11. [PMID: 29760959 PMCID: PMC5944420 DOI: 10.1556/1886.2018.00002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [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: 01/21/2018] [Accepted: 01/31/2018] [Indexed: 12/16/2022] Open
Abstract
Introduction We assessed the molecular epidemiology of multidrug-resistant bacteria colonizing or infecting war-injured patients from Libya and Syria who were treated at the Bundeswehr hospitals Hamburg and Westerstede, Germany. Methods Enterobacteriaceae and Gram-negative rod-shaped nonfermentative bacteria with resistance against third-generation methoxyimino cephalosporins or carbapenems as well as methicillin-resistant Staphylococcus aureus (MRSA) from war-injured patients from Libya and Syria were assessed by molecular typing, i.e., spa typing for MRSA strains and rep-PCR and next-generation sequencing (NGS) for Gram-negative isolates. Results A total of 66 isolates were assessed – comprising 44 Enterobacteriaceae, 16 nonfermentative rod-shaped bacteria, and 6 MRSA from 22 patients – and 8 strains from an assessment of the patient environment comprising 5 Enterobacteriaceae and 3 nonfermentative rod-shaped bacteria. Although 24 out of 66 patient strains were isolated more than 3 days after hospital admission, molecular typing suggested only 7 likely transmission events in the hospitals. Identified clonal clusters primarily suggested transmission events in the country of origin or during the medical evacuation flights. Conclusions Nosocomial transmissions in hospital can be efficiently prevented by hygiene precautions in spite of heavy colonization. Transmission prior to hospital admission like on evacuation flights or in crises zones needs further assessment.
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Affiliation(s)
- Hagen Frickmann
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Hamburg, Hamburg, Germany.,Institute of Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
| | - Thomas Köller
- Institute of Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
| | - Ralf Matthias Hagen
- Department of Preventive Medicine, Bundeswehr Medical Academy, Munich, Germany
| | - Klaus-Peter Ebert
- Hygiene Department, Bundeswehr Hospital Westerstede, Westerstede, Germany
| | - Martin Müller
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Berlin, Berlin, Germany
| | - Werner Wenzel
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Hamburg, Hamburg, Germany.,Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Berlin, Berlin, Germany
| | - Renate Gatzer
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Berlin, Berlin, Germany
| | - Ulrich Schotte
- Laboratory Department II, Central Institute of the Bundeswehr Kiel, Kiel-Kronshagen, Germany
| | - Alfred Binder
- Laboratory Department II, Central Institute of the Bundeswehr Kiel, Kiel-Kronshagen, Germany
| | - Romy Skusa
- Institute of Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
| | - Philipp Warnke
- Institute of Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
| | - Andreas Podbielski
- Institute of Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
| | - Christian Rückert
- Centrum for Biotechnology (CeBiTec), University Bielefeld, Bielefeld, Germany
| | - Bernd Kreikemeyer
- Institute of Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
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Affiliation(s)
- Walter Baukloh
- Eisenhüttenmannischen Institut der Technischen Hochschule; Berlin
| | - Werner Wenzel
- Eisenhüttenmannischen Institut der Technischen Hochschule; Berlin
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Strunk T, Wolf M, Brieg M, Klenin K, Biewer A, Tristram F, Ernst M, Kleine PJ, Heilmann N, Kondov I, Wenzel W. SIMONA 1.0: an efficient and versatile framework for stochastic simulations of molecular and nanoscale systems. J Comput Chem 2012; 33:2602-13. [PMID: 22886395 DOI: 10.1002/jcc.23089] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 07/24/2012] [Accepted: 07/25/2012] [Indexed: 11/05/2022]
Abstract
Molecular simulation methods have increasingly contributed to our understanding of molecular and nanoscale systems. However, the family of Monte Carlo techniques has taken a backseat to molecular dynamics based methods, which is also reflected in the number of available simulation packages. Here, we report the development of a generic, versatile simulation package for stochastic simulations and demonstrate its application to protein conformational change, protein-protein association, small-molecule protein docking, and simulation of the growth of nanoscale clusters of organic molecules. Simulation of molecular and nanoscale systems (SIMONA) is easy to use for standard simulations via a graphical user interface and highly parallel both via MPI and the use of graphical processors. It is also extendable to many additional simulations types. Being freely available to academic users, we hope it will enable a large community of researchers in the life- and materials-sciences to use and extend SIMONA in the future. SIMONA is available for download under http://int.kit.edu/nanosim/simona.
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Affiliation(s)
- T Strunk
- Institute of Nanotechnology, Karlsruhe Institute of Technology, PO Box 3640, 76021 Karlsruhe, Germany
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Navarro-Fernández J, Pérez-Sánchez H, Martínez-Martínez I, Meliciani I, Guerrero JA, Vicente V, Corral J, Wenzel W. In silico discovery of a compound with nanomolar affinity to antithrombin causing partial activation and increased heparin affinity. J Med Chem 2012; 55:6403-12. [PMID: 22742452 DOI: 10.1021/jm300621j] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The medical and socioeconomic relevance of thromboembolic disorders promotes an ongoing effort to develop new anticoagulants. Heparin is widely used as activator of antithrombin but incurs side effects. We screened a large database in silico to find alternative molecules and predicted d-myo-inositol 3,4,5,6-tetrakisphosphate (TMI) to strongly interact with antithrombin. Isothermal titration calorimetry confirmed a TMI affinity of 45 nM, higher than the heparin affinity (273 nM). Functional studies, fluorescence analysis, and citrullination experiments revealed that TMI induced a partial activation of antithrombin that facilitated the interaction with heparin and low affinity heparins. TMI improved antithrombin inhibitory function of plasma from homozygous patients with antithrombin deficiency with a heparin binding defect and also in a model with endothelial cells. Our in silico screen identified a new, non-polysaccharide scaffold able to interact with the heparin binding domain of antithrombin. The functional consequences of this interaction were experimentally characterized and suggest potential anticoagulant therapeutic applications.
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Affiliation(s)
- J Navarro-Fernández
- Servicio de Hematología y Oncología Médica, H. U. Morales Meseguer, Centro Regional de Hemodonación, University of Murcia, Spain
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12
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Starikov E, Quintilla A, Nganou C, Lee K, Cuniberti G, Wenzel W. Single-molecule DNA conductance in water solutions: Role of DNA low-frequency dynamics. Chem Phys Lett 2009. [DOI: 10.1016/j.cplett.2008.11.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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13
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Xie FQ, Maul R, Augenstein A, Obermair C, Starikov EB, Schön G, Schimmel T, Wenzel W. Independently switchable atomic quantum transistors by reversible contact reconstruction. Nano Lett 2008; 8:4493-4497. [PMID: 19367974 DOI: 10.1021/nl802438c] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The controlled fabrication of actively switchable atomic-scale devices, in particular transistors, has remained elusive to date. Here, we explain the operation of an atomic-scale three-terminal device by a novel switching mechanism of bistable, self-stabilizing reconstruction of the electrode contacts at the atomic level: While the device is manufactured by electrochemical deposition, it operates entirely on the basis of mechanical effects of the solid-liquid interface. We analyze mechanically and thermally stable metallic junctions with a predefined quantized conductance of 1-5 G0 in experiment and atomistic simulation. Atomistic modeling of structural and conductance properties elucidates bistable electrode reconstruction as the underlying mechanism of the device. Independent room temperature operation of two transistors at low voltage demonstrates intriguing perspectives for quantum electronics and logics on the atomic scale.
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Affiliation(s)
- F Q Xie
- Institut für Angewandte Physik, DFG-Center for Functional Nanostructures, Universität Karlsruhe, 76128 Karlsruhe, Germany
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14
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15
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Franke J, Wenzel W, Rehfuss D, Keiner HP, Manncke K. [Acute carpal tunnel syndrome in a patient with Marfan syndrome]. Unfallchirurg 2008; 111:358-60. [PMID: 18438636 DOI: 10.1007/s00113-007-1329-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Acute carpal tunnel syndrome (ACTS) is rare and is mostly the result of fractures of the distal radius or the carpal bones. This paper gives the first report of an ACTS following contusion of the wrist as the result of an extensive haematoma of the flexor tendon sheath, which did not appear until 50 hours after the injury was sustained but then developed rapidly. The patient suffers from Marfan syndrome. This disease is associated with pathologic changes to the major vessels, and especially the aorta, and of the smaller peripheral vessels. It is assumed that the haematoma arose from an aneurysm of such a small vessel. The treatment of choice in ACTS is emergency incision of the carpal tunnel.
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Affiliation(s)
- J Franke
- BG Unfallklinik Ludwigshafen, Klinik für Unfallchirurgie und Orthopädie, Ludwigshafen, Germany.
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16
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Kwiatkowski JJ, Nelson J, Li H, Bredas JL, Wenzel W, Lennartz C. Simulating charge transport in tris(8-hydroxyquinoline) aluminium (Alq3). Phys Chem Chem Phys 2008; 10:1852-8. [DOI: 10.1039/b719592c] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.2] [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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17
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Abstract
An important contribution to today's computer-aided drug design is the automated screening of large compound databases against structurally resolved protein receptors targets. The introduction of ligand flexibility has, by now, become a standardized procedure. In contrast, a general approach to treat target degrees of freedom is still to be found, a consequence of the extreme increase of computational complexity, which comes along with the relaxation of protein degrees of freedom. In this chapter, we discuss in some detail both benefits and present limitations of target flexibility for high-throughput in silico database screens. Among the benefits are an improved diversity of binding modes, which allows one to identify a wider class of drug candidates. The limitations are related to a diminishing docking accuracy and an increased number of false hits. Using the thymidine kinase receptor and ten known inhibitors as an example, we describe in detail how target flexibility was implemented and how it affected the screening performance.
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Affiliation(s)
- B Fischer
- Institut für Nanotechnologie, Forschungszentrum Karlsruhe, Karlsruhe, Germany
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18
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Junne S, Wenzel W, Szewzyk U, Götz P. Screening nach und Charakterisierung von Biotensiden aus Tiefsee-Isolaten. CHEM-ING-TECH 2006. [DOI: 10.1002/cite.200650303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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19
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Smith DY, Paus HJ, Rapp M, Wenzel W. Impurity-ligand effects on the magneto-optically measured spin-orbit splitting of trapped electron centres. ACTA ACUST UNITED AC 2006. [DOI: 10.1080/00337578308218629] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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20
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Starikov EB, Fujita T, Watanabe H, Sengoku Y, Tanaka S, Wenzel W. Effects of molecular motion on charge transfer/transport through DNA duplexes with and without base pair mismatch. Molecular Simulation 2006. [DOI: 10.1080/08927020600835673] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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21
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Abstract
We have performed theoretical multiconfigurational calculations of the molecular energy levels based on two axial ligand field models and determined the model parameters to reproduce ab initio energies of TiCl(2), TiF(2), VCl(2), and VF(2). We develop two extensions to ligand field theory (LFT) for linear transition metal dihalides, which are incorrectly described by standard LFT. The standard LFT is augmented (1) by including the ligand induced hybridization of the d(sigma) orbital with the 4s orbital or (2) by using a different radial part for the d(sigma) orbital. Both models reproduce the energies of the first electronic states in very good agreement with numerical multireference configuration interaction results. Furthermore the model parameters are very close to experimental known Racah parameters describing the term energies of Ti(2+) and V(2+).
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Affiliation(s)
- M Vogel
- Institut für Physik, Universität Dortmund, D-44221 Dortmund, Germany
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22
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Abstract
We have investigated an evolutionary algorithm for de novo all-atom folding of the bacterial ribosomal protein L20. We report results of two simulations that converge to near-native conformations of this 60-amino-acid, four-helix protein. We observe a steady increase of "native content" in both simulated ensembles and a large number of near-native conformations in their final populations. We argue that these structures represent a significant fraction of the low-energy metastable conformations, which characterize the folding funnel of this protein. These data validate our all-atom free-energy force field PFF01 for tertiary structure prediction of a previously inaccessible structural family of proteins. We also compare folding simulations of the evolutionary algorithm with the basin-hopping technique for the Trp-cage protein. We find that the evolutionary algorithm generates a dynamic memory in the simulated population, which leads to faster overall convergence.
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Affiliation(s)
- A Schug
- Forschungszentrum Karlsruhe, Institut für Nanotechnologie, 76021 Karlsruhe, Germany
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23
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Abstract
We investigate different protocols of the basin hopping technique for de novo protein folding. Using the protein free-energy force field PFF01 we report the reproducible all-atom folding of the 20-amino-acid tryptophan-cage protein [Protein Data Bank (PDB) code: 112y] and of the recently discovered 26-amino-acid potassium channel blocker (PDB code: 1wqc), which exhibits an unusual fold. We find that simulations with increasing cycle length and random starting temperatures perform best in comparison with other parametrizations. The basin hopping technique emerges as a simple but very efficient and robust workhorse for all-atom protein folding.
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Affiliation(s)
- A Verma
- Forschungszentrum Karlsruhe GmbH, Institut für Wissenschaftliches Rechnen, Postfach 3640, D-76021 Karlsruhe, Germany
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24
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Starikov EB, Tanaka S, Kurita N, Sengoku Y, Natsume T, Wenzel W. Investigation of a Kubo-formula-based approach to estimate DNA conductance in an atomistic model. Eur Phys J E Soft Matter 2005; 18:437-45. [PMID: 16314916 DOI: 10.1140/epje/e2005-00047-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2005] [Indexed: 05/05/2023]
Abstract
A novel approach to estimate DNA conductance based upon Kubo formula is presented and discussed. Using this approach, the effects of base pair mismatches, different conformational changes and base pair sequence on DNA electrical properties were investigated. The results were compared with the data from other methods. The new approach makes possible very fast estimation of conductance spectra for oligonucleotides with hundreds of base pairs and can easily be extended to treat arbitrary chemical modifications of DNA.
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Affiliation(s)
- E B Starikov
- Research Center Karlsruhe, Institute for Nanotechnology, 76021 Karlsruhe, Germany.
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25
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Abstract
We investigated the electronic structure of two members of the transition-metal dihalide family, VF(2) and VCl(2). Using the configuration-interaction method in large basis sets we calculated the lowest 17 states of these molecules in the vicinity of their ground-state geometry. We compute the ground-state bond lengths, vibrational frequencies, and dissociation energies. In contrast to predictions of ligand-field theory, we find (4)Sigma(g) (-) ground states for both molecules.
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Affiliation(s)
- M Vogel
- Institut für Physik, Universität Dortmund, D-44221 Dortmund, Germany
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26
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27
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Herges T, Wenzel W. In silico folding of a three helix protein and characterization of its free-energy landscape in an all-atom force field. Phys Rev Lett 2005; 94:018101. [PMID: 15698135 DOI: 10.1103/physrevlett.94.018101] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2003] [Indexed: 05/24/2023]
Abstract
We report the reproducible first-principles folding of the 40 amino-acid, three-helix headpiece of the HIV accessory protein in a recently developed all-atom free-energy force field. Six of 20 simulations using an adapted basin-hopping method converged to better than 3 A backbone rms deviation to the experimental structure. Using over 60 000 low-energy conformations of this protein, we constructed a decoy tree that completely characterizes its folding funnel.
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Affiliation(s)
- T Herges
- Forschungszentrum Karlsruhe, Institut für Nanotechnologie, 76021 Karlsruhe, Germany
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28
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Stampfuss P, Wenzel W. Improved implementation and application of the individually selecting configuration interaction method. J Chem Phys 2005; 122:024110. [PMID: 15638575 DOI: 10.1063/1.1829045] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report on the progress of our implementation of the configuration-selecting multireference configuration interaction method on massively parallel architectures with distributed memory, which now permits the treatment of Hilbert spaces of dimension O(10(12)). Of these about 50,000,000 can be selected in the variational subspace. We provide scaling data for the running time of the code for the IBM/SP3 and the CRAY-T3E. We present benchmark results for two selected applications: the energetics of the isomers of dinitrosoethylene and the benchmark results for the ring closure reaction of enediyene.
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Affiliation(s)
- P Stampfuss
- Forschungszentrum Karlsruhe, Institut für Nanotechnologie, Postfach 3640, 76021 Karlsruhe, Germany
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29
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Abstract
We have developed an all-atom free-energy force field (PFF01) for protein tertiary structure prediction. PFF01 is based on physical interactions and was parameterized using experimental structures of a family of proteins believed to span a wide variety of possible folds. It contains empirical, although sequence-independent terms for hydrogen bonding. Its solvent-accessible surface area solvent model was first fit to transfer energies of small peptides. The parameters of the solvent model were then further optimized to stabilize the native structure of a single protein, the autonomously folding villin headpiece, against competing low-energy decoys. Here we validate the force field for five nonhomologous helical proteins with 20-60 amino acids. For each protein, decoys with 2-3 A backbone root mean-square deviation and correct experimental Cbeta-Cbeta distance constraints emerge as those with the lowest energy.
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Affiliation(s)
- T Herges
- Forschungszentrum Karlsruhe, Institut für Nanotechnologie, Karlsruhe, Germany
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30
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31
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Abstract
Using a cascadic version of the stochastic tunneling method we perform an all-atom database screen over 186,000 flexible ligands of the NCI 3D database against the thymidine kinase receptor. By analyzing the errors in the binding energy we demonstrate how the cascadic technique is superior to conventional sequential docking techniques and how reliable results for the determination of the top-scoring ligands could be achieved. The substrate corresponding to the crystal structure used in the screen ranks in the upper 0.05% of the database, validating both docking methodology and the applicability of the scoring function to this substrate. Several high ranking ligands of the database display significant structural similarity with known substrates. A detailed analysis of the accuracy of the screening method is carried out, and its dependence on the flexibility of the ligand is quantified.
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Affiliation(s)
- H Merlitz
- Forschungszentrum Karlsruhe GmbH, Institut für Nanotechnologie, Postfach 3640, D-76021 Karlsruhe, Germany.
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32
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Abstract
All-atom protein structure prediction from the amino acid sequence alone remains an important goal of biophysical chemistry. Recent progress in force field development and validation suggests that the PFF01 free-energy force field correctly predicts the native conformation of various helical proteins as the global optimum of its free-energy surface. Reproducible protein structure prediction requires the availability of efficient optimization methods to locate the global minima of such complex potentials. Here we investigate an adapted version of the parallel tempering method as an efficient parallel stochastic optimization method for protein structure prediction. Using this approach we report the reproducible all-atom folding of the three-helix 40 amino acid HIV accessory protein from random conformations to within 2.4 A backbone RMS deviation from the experimental structure with modest computational resources.
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Affiliation(s)
- A Schug
- Forschungszentrum Karlsruhe, Institut für Nanotechnologie, 76021 Karlsruhe, Germany
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33
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Abstract
We report the reproducible folding of the 20 amino-acid protein trp cage using a novel version of the stochastic tunneling method and a recently developed all-atom protein free-energy force field. Six of 25 simulations reached an energy within 1 kcal/mol of the best energy, all of which correctly predicted the native experimental structure of the protein, in total eight simulations converged to the native structure. We find a strong correlation between energy and root-mean-square deviation to the native structure for all simulations.
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Affiliation(s)
- A Schug
- Forschungszentrum Karlsruhe, Institut für Nanotechnologie, 76021 Karlsruhe, Germany
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34
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Uptmoor R, Wenzel W, Friedt W, Donaldson G, Ayisi K, Ordon F. Comparative analysis on the genetic relatedness of Sorghum bicolor accessions from Southern Africa by RAPDs, AFLPs and SSRs. Theor Appl Genet 2003; 106:1316-1325. [PMID: 12748784 DOI: 10.1007/s00122-003-1202-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2002] [Accepted: 09/24/2002] [Indexed: 05/24/2023]
Abstract
In order to get an overview on the genetic relatedness of sorghum (Sorghum bicolor) landraces and cultivars grown in low-input conditions of small-scale farming systems, 46 sorghum accessions derived from Southern Africa were evaluated on the basis of amplified fragment length polymorphism (AFLPs), random amplified polymorphic DNAs (RAPDs) and simple sequence repeats (SSRs). By this approach all sorghum accessions were uniquely fingerprinted by all marker systems. Mean genetic similarity was estimated at 0.88 based on RAPDs, 0.85 using AFLPs and 0.31 based on SSRs. In addition to this, genetic distance based on SSR data was estimated at 57 according to a stepwise mutation model (Deltamu-SSR). All UPGMA-clusters showed a good fit to the similarity estimates (AFLPs: r = 0.92; RAPDs: r = 0.88; SSRs: r = 0.87; Deltamu-SSRs: r = 0.85). By UPGMA-clustering two main clusters were built on all marker systems comprising landraces on the one hand and newly developed varieties on the other hand. Further sub-groupings were not unequivocal. Genetic diversity (H, DI) was estimated on a similar level within landraces and breeding varieties. Comparing the three approaches to each other, RAPD and AFLP similarity indices were highly correlated (r = 0.81), while the Spearman's rank correlation coefficient between SSRs and AFLPs was r = 0.57 and r = 0.51 between RAPDs and SSRs. Applying a stepwise mutation model on the SSR data resulted in an intermediate correlation coefficient between Deltamu-SSRs and AFLPs (r = 0.66) and RAPDs ( r = 0.67), respectively, while SSRs and Deltamu-SSRs showed a lower correlation coefficient (r = 0.52). The highest bootstrap probabilities were found using AFLPs (56% on average) while SSR, Deltamu-SSR and RAPD-based similarity estimates had low mean bootstrap probabilities (24%, 27%, 30%, respectively). The coefficient of variation (CV) of the estimated genetic similarity decreased with an increasing number of bands and was lowest using AFLPs.
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Affiliation(s)
- R Uptmoor
- Institute for Crop Science and Plant Breeding I, Justus-Liebig-University, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
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35
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Hettler MH, Wenzel W, Wegewijs MR, Schoeller H. Current collapse in tunneling transport through benzene. Phys Rev Lett 2003; 90:076805. [PMID: 12633261 DOI: 10.1103/physrevlett.90.076805] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2002] [Indexed: 05/24/2023]
Abstract
We investigate the electrical transport through a system of benzene coupled to metal electrodes by electron tunneling. Using electronic structure calculations, a semiquantitative model for the pi electrons of the benzene is derived that includes general two-body interactions. After exact diagonalization of the benzene model the transport is computed using perturbation theory for weak electrode-benzene coupling (golden rule approximation). We include the effect of an applied electric field on the molecular states, as well as radiative relaxation. We predict a current collapse and strong negative differential conductance due to a "blocking" state when the electrode is coupled to the para-position of benzene. In contrast, for coupling to the meta-position, a series of steps in the I-V curve is found.
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Affiliation(s)
- M H Hettler
- Forschungszentrum Karlsruhe, Institut für Nanotechnologie, 76021 Karlsruhe, Germany
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36
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Hamacher K, Stolze J, Wenzel W. Disorder induced quantum phase transition in random-exchange spin-1/2 chains. Phys Rev Lett 2002; 89:127202. [PMID: 12225120 DOI: 10.1103/physrevlett.89.127202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2001] [Indexed: 05/23/2023]
Abstract
We investigate the effect of quenched bond disorder on the anisotropic antiferromagnetic spin-1/2 (XXZ) chain as a model for disorder-induced quantum phase transitions. We find nonuniversal behavior of the average correlation functions for weak disorder, followed by a quantum phase transition into a strongly disordered phase with only short-range xy correlations. We find no evidence for the universal strong-disorder fixed point predicted by the real-space renormalization group, suggesting a qualitatively different view of the relationship between quantum fluctuations and disorder.
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Affiliation(s)
- K Hamacher
- Forschungszentrum Karlsruhe, Institut für Nanotechnologie, 76021 Karlsruhe, Germany
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37
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Heurich J, Cuevas JC, Wenzel W, Schön G. Electrical transport through single-molecule junctions: from molecular orbitals to conduction channels. Phys Rev Lett 2002; 88:256803. [PMID: 12097112 DOI: 10.1103/physrevlett.88.256803] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2001] [Indexed: 05/23/2023]
Abstract
We present an atomistic theory of electronic transport through single organic molecules that reproduces the important features of the current-voltage ( I-V) characteristics observed in recent experiments. We trace these features to their origin in the electronic structure of the molecules and their local atomic environment. We demonstrate how conduction channels arise from the molecular orbitals and elucidate the contributions of individual orbitals to the current. We find that in thiol-bridged aromatic molecules many molecular orbitals contribute to a single conduction channel and discuss the implications of this result for the design of molecular devices.
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Affiliation(s)
- J Heurich
- Institut für Theoretische Festkörperphysik, Universität Karlsruhe, 76128 Karlsruhe, Germany
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38
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Weirich J, Wenzel W. [Current classification of anti-arrhythmia agents]. Z Kardiol 2000; 89 Suppl 3:62-7. [PMID: 10810787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Antiarrhythmic drugs can be divided into four Vaughan Williams classes (I-IV) according to defined electrophysiological effects on the myocardium. Thus, the Vaughan Williams classification also coincides with the main myocardial targets of the antiarrhythmics, i.e., myocardial sodium-, potassium-, and calcium-channels or beta-adrenergic receptors. A more detailed characterization which is also based on the myocardial targets of a drug is given by the "Sicilian Gambit" approach of classification. Nevertheless, the appropriate drug for the management of a given clinical arrhythmia has to be chosen according to the electrophysiological effects of the respective drug. A main determinant of the antiarrhythmic or proarrhythmic properties of a drug is the frequency dependence of its electrophysiological effects. The sodium-channel blockade induced by class-I substances is enhanced with increasing heart rates. Thus, class-I antiarrhythmics can be subclassified as substances showing a more exponential, an approximately linear, or rather saturated block-frequency relation. Class-III antiarrhythmics (potassium-channel blockade) can be further differentiated according to the component of the delayed rectifier potassium current (IK) which is inhibited by a drug. Class-III drugs inhibiting selectively the rapidly activating and deactivating IKr component exhibit a marked reverse rate dependence, i.e., the drug induced prolongation of the cardiac action potential is minimized at high rates. On the other hand, during bradycardia the pronounced action potential prolongation may cause early afterdepolarizations and triggered activity leading to torsades de pointes arrhythmias (acquired QT syndrome). Class-III substances inhibiting the slowly activating IKs component are currently under investigation and are expected to show a direct rate dependence. Experimental data available so far point to an action potential prolonging effect at least independent of rate. However, it is uncertain whether proarrhythmic effects can be thus avoided, especially in light of the fact that one form of congenital QT syndrome (LQT1) seems to be linked to dysfunction of the IKs-channel.
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Affiliation(s)
- J Weirich
- Physiologisches Institut der Universität, Freiburg
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39
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40
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Stephan F, Wenzel W. An algorithm for the multi-reference configuration interaction method on distributed memory architectures. J Chem Phys 1998. [DOI: 10.1063/1.475464] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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41
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Muthukumar VN, Gros C, Wenzel W, Valentí R, Lemmens P, Eisener B, Güntherodt G, Weiden M, Geibel C, Steglich F. Frustration-induced Raman scattering in CuGeO3. Phys Rev B Condens Matter 1996; 54:R9635-R9638. [PMID: 9984779 DOI: 10.1103/physrevb.54.r9635] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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42
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43
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44
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Sarker S, Jayaprakash C, Krishnamurthy HR, Wenzel W. Spiral states in the square-lattice Hubbard model. Phys Rev B Condens Matter 1991; 43:8775-8778. [PMID: 9996544 DOI: 10.1103/physrevb.43.8775] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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45
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46
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47
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Krishnamurthy HR, Jayaprakash C, Sarker S, Wenzel W. Mott-Hubbard metal-insulator transition in nonbipartite lattices. Phys Rev Lett 1990; 64:950-953. [PMID: 10042122 DOI: 10.1103/physrevlett.64.950] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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48
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49
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Affiliation(s)
- M Frasch
- Department of Plant Physiology, University of Hohenheim, Stuttgart, FRG
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Steinbauer J, Wenzel W, Hess D. Nucleotide and deduced amino acid sequences of the Klebsiella pneumoniae nifK gene coding for the beta-subunit of nitrogenase MoFe protein. Nucleic Acids Res 1988; 16:7199. [PMID: 3043382 PMCID: PMC338380 DOI: 10.1093/nar/16.14.7199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Affiliation(s)
- J Steinbauer
- Department of Plant Physiology, University of Hohenheim, Stuttgart, FRG
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