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Kass D, Larson VA, Corona T, Kuhlmann U, Hildebrandt P, Lohmiller T, Bill E, Lehnert N, Ray K. Trapping of a phenoxyl radical at a non-haem high-spin iron(II) centre. Nat Chem 2024; 16:658-665. [PMID: 38216752 DOI: 10.1038/s41557-023-01405-9] [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] [Received: 12/30/2018] [Accepted: 11/17/2023] [Indexed: 01/14/2024]
Abstract
The activation of dioxygen at haem and non-haem metal centres, and subsequent functionalization of unactivated C‒H bonds, has been a focal point of much research. In iron-mediated oxidation reactions, O2 binding at an iron(II) centre is often accompanied by an oxidation of the iron centre. Here we demonstrate dioxygen activation by sodium tetraphenylborate and protons in the presence of an iron(II) complex to form a reactive radical species, whereby the iron oxidation state remains unaltered in the presence of a highly oxidizing phenoxyl radical and O2. This complex, containing an unusual iron(II)-phenoxyl radical motif, represents an elusive example of a spectroscopically characterized oxygen-derived iron(II)-reactive intermediate during chemical and biological dioxygen activation at haem and non-haem iron active centres. The present report opens up strategies for the stabilization of a phenoxyl radical cofactor, with its full oxidizing capabilities, to act as an independent redox centre next to an iron(II) site during substrate oxidation reactions.
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Affiliation(s)
- Dustin Kass
- Department of Chemistry, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Virginia A Larson
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, MI, USA
| | - Teresa Corona
- Department of Chemistry, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Uwe Kuhlmann
- Department of Chemistry, Technische Universität Berlin, Berlin, Germany
| | - Peter Hildebrandt
- Department of Chemistry, Technische Universität Berlin, Berlin, Germany
| | - Thomas Lohmiller
- Department of Chemistry, Humboldt-Universität zu Berlin, Berlin, Germany
- EPR4Energy Joint Lab, Department Spins in Energy Conversion and Quantum Information Science, Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany
| | - Eckhard Bill
- Max-Planck-Institut für Chemische Energiekonversion, Mülheim an der Ruhr, Germany
| | - Nicolai Lehnert
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, MI, USA.
| | - Kallol Ray
- Department of Chemistry, Humboldt-Universität zu Berlin, Berlin, Germany.
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2
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Devi T, Dutta K, Deutscher J, Mebs S, Kuhlmann U, Haumann M, Cula B, Dau H, Hildebrandt P, Ray K. A high-spin alkylperoxo-iron(iii) complex with cis-anionic ligands: implications for the superoxide reductase mechanism. Chem Sci 2024; 15:528-533. [PMID: 38179538 PMCID: PMC10762717 DOI: 10.1039/d3sc05603a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 12/05/2023] [Indexed: 01/06/2024] Open
Abstract
The N3O macrocycle of the 12-TMCO ligand stabilizes a high spin (S = 5/2) [FeIII(12-TMCO)(OOtBu)Cl]+ (3-Cl) species in the reaction of [FeII(12-TMCO)(OTf)2] (1-(OTf)2) with tert-butylhydroperoxide (tBuOOH) in the presence of tetraethylammonium chloride (NEt4Cl) in acetonitrile at -20 °C. In the absence of NEt4Cl the oxo-iron(iv) complex 2 [FeIV(12-TMCO)(O)(CH3CN)]2+ is formed, which can be further converted to 3-Cl by adding NEt4Cl and tBuOOH. The role of the cis-chloride ligand in the stabilization of the FeIII-OOtBu moiety can be extended to other anions including the thiolate ligand relevant to the enzyme superoxide reductase (SOR). The present study underlines the importance of subtle electronic changes and secondary interactions in the stability of the biologically relevant metal-dioxygen intermediates. It also provides some rationale for the dramatically different outcomes of the chemistry of iron(iii)peroxy intermediates formed in the catalytic cycles of SOR (Fe-O cleavage) and cytochrome P450 (O-O bond lysis) in similar N4S coordination environments.
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Affiliation(s)
- Tarali Devi
- Institut für Chemie, Humboldt-Universitat zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
- Department of Inorganic and Physical Chemistry, Indian Institute of Science Bangalore Karnataka-560012 India
| | - Kuheli Dutta
- Institut für Chemie, Humboldt-Universitat zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Jennifer Deutscher
- Institut für Chemie, Humboldt-Universitat zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Stefan Mebs
- Department of Physics, Freie Universität Berlin Arnimallee 14 14195 Berlin Germany
| | - Uwe Kuhlmann
- Institut für Chemie, Technische Universität Berlin Fakultät II, Straße des 17. Juni 135 10623 Berlin Germany
| | - Michael Haumann
- Department of Physics, Freie Universität Berlin Arnimallee 14 14195 Berlin Germany
| | - Beatrice Cula
- Institut für Chemie, Humboldt-Universitat zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Holger Dau
- Department of Physics, Freie Universität Berlin Arnimallee 14 14195 Berlin Germany
| | - Peter Hildebrandt
- Institut für Chemie, Technische Universität Berlin Fakultät II, Straße des 17. Juni 135 10623 Berlin Germany
| | - Kallol Ray
- Institut für Chemie, Humboldt-Universitat zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
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3
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Battistella B, Lohmiller T, Cula B, Hildebrandt P, Kuhlmann U, Dau H, Mebs S, Ray K. A New Thiolate-Bound Dimanganese Cluster as a Structural and Functional Model for Class Ib Ribonucleotide Reductases. Angew Chem Int Ed Engl 2023; 62:e202217076. [PMID: 36583430 DOI: 10.1002/anie.202217076] [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] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Revised: 12/24/2022] [Accepted: 12/29/2022] [Indexed: 12/31/2022]
Abstract
In class Ib ribonucleotide reductases (RNRs) a dimanganese(II) cluster activates superoxide (O2 ⋅- ) rather than dioxygen (O2 ), to access a high valent MnIII -O2 -MnIV species, responsible for the oxidation of tyrosine to tyrosyl radical. In a biomimetic approach, we report the synthesis of a thiolate-bound dimanganese complex [MnII 2 (BPMT)(OAc)2 ](ClO)4 (BPMT=(2,6-bis{[bis(2-pyridylmethyl)amino]methyl}-4-methylthiophenolate) (1) and its reaction with O2 ⋅- to form a [(BPMT)MnO2 Mn]2+ complex 2. Resonance Raman investigation revealed the presence of an O-O bond in 2, while EPR analysis displayed a 16-line St =1/2 signal at g=2 typically associated with a MnIII MnIV core, as detected in class Ib RNRs. Unlike all other previously reported Mn-O2 -Mn complexes, generated by O2 ⋅- activation at Mn2 centers, 2 proved to be a capable electrophilic oxidant in aldehyde deformylation and phenol oxidation reactions, rendering it one of the best structural and functional models for class Ib RNRs.
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Affiliation(s)
- Beatrice Battistella
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Thomas Lohmiller
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany.,EPR4Energy Joint Lab, Department Spins in Energy Conversion and Quantum Information Science, Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 16, 12489, Berlin, Germany
| | - Beatrice Cula
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Peter Hildebrandt
- Institut für Chemie, Fakultät II, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Uwe Kuhlmann
- Institut für Chemie, Fakultät II, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Holger Dau
- Institut für Physik, Freie Universität zu Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Stefan Mebs
- Institut für Physik, Freie Universität zu Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Kallol Ray
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
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4
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Battistella B, Iffland-Mühlhaus L, Schütze M, Cula B, Kuhlmann U, Dau H, Hildebrandt P, Lohmiller T, Mebs S, Apfel UP, Ray K. Evidence of Sulfur Non-Innocence in [Co II (dithiacyclam)] 2+ -Mediated Catalytic Oxygen Reduction Reactions. Angew Chem Int Ed Engl 2023; 62:e202214074. [PMID: 36378951 PMCID: PMC10108118 DOI: 10.1002/anie.202214074] [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] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 11/10/2022] [Accepted: 11/14/2022] [Indexed: 11/16/2022]
Abstract
In many metalloenzymes, sulfur-containing ligands participate in catalytic processes, mainly via the involvement in electron transfer reactions. In a biomimetic approach, we now demonstrate the implication of S-ligation in cobalt mediated oxygen reduction reactions (ORR). A comparative study between the catalytic ORR capabilities of the four-nitrogen bound [Co(cyclam)]2+ (1; cyclam=1,5,8,11-tetraaza-cyclotetradecane) and the S-containing analog [Co(S2 N2 -cyclam)]2+ (2; S2 N2 -cyclam=1,8-dithia-5,11-diaza-cyclotetradecane) reveals improved catalytic performance once the chalcogen is introduced in the Co coordination sphere. Trapping and characterization of the intermediates formed upon dioxygen activation at the CoII centers in 1 and 2 point to the involvement of sulfur in the O2 reduction process as the key for the improved catalytic ORR capabilities of 2.
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Affiliation(s)
- Beatrice Battistella
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Linda Iffland-Mühlhaus
- Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, Universitätsstraße 150, 44780, Bochum, Germany
| | - Maximillian Schütze
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Beatrice Cula
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Uwe Kuhlmann
- Institut für Chemie, Fakultät II, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Holger Dau
- Institut für Physik, Freie Universität zu Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Peter Hildebrandt
- Institut für Chemie, Fakultät II, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Thomas Lohmiller
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany.,EPR4Energy Joint Lab, Department Spins in Energy Conversion and Quantum Information Science, Helmholtz Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Str. 16, 12489, Berlin, Germany
| | - Stefan Mebs
- Institut für Physik, Freie Universität zu Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Ulf-Peter Apfel
- Faculty of Chemistry and Biochemistry, Ruhr-Universität Bochum, Universitätsstraße 150, 44780, Bochum, Germany.,Department for Electrosynthesis, Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT, Osterfelder Str. 3, 46047, Oberhausen, Germany
| | - Kallol Ray
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
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5
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Battistella B, Lohmiller T, Cula B, Hildebrandt P, Kuhlmann U, Dau H, Mebs S, Ray K. A Thiolate‐Bound Dimanganese Cluster as a Structural and Functional Model for Class Ib Ribonucleotide Reductases. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202217076] [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: 01/01/2023]
Affiliation(s)
- Beatrice Battistella
- Humboldt University of Berlin: Humboldt-Universitat zu Berlin Department of Chemistry GERMANY
| | - Thomas Lohmiller
- Humboldt-Universität zu Berlin: Humboldt-Universitat zu Berlin Department of Chemistry GERMANY
| | - Beatrice Cula
- Humboldt University of Berlin: Humboldt-Universitat zu Berlin Department of Chemistry GERMANY
| | - Peter Hildebrandt
- TU Berlin: Technische Universitat Berlin Institut für Chemie GERMANY
| | - Uwe Kuhlmann
- TU Berlin University: Technische Universitat Berlin Institut für Chemie GERMANY
| | - Holger Dau
- FU Berlin: Freie Universitat Berlin Institut für Physik GERMANY
| | - Stefan Mebs
- FU Berlin: Freie Universitat Berlin Institut für Physik GERMANY
| | - Kallol Ray
- Humboldt university Institute of chemistry Brook-taylor strasse 2 12489 Berlin GERMANY
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6
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Battistella B, Iffland-Mühlhaus L, Schütze M, Cula B, Kuhlmann U, Dau H, Hildebrandt P, Lohmiller T, Mebs S, Apfel UP, Ray K. Evidence of Sulfur Non‐Innocence in [CoII(dithiacyclam)]2+‐Mediated Catalytic Oxygen Reduction Reactions. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202214074] [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: 11/16/2022]
Affiliation(s)
- Beatrice Battistella
- Humboldt-Universität zu Berlin: Humboldt-Universitat zu Berlin Chemistry GERMANY
| | - Linda Iffland-Mühlhaus
- Ruhr-Universität Bochum: Ruhr-Universitat Bochum Faculty of Chemistry and Biochemistry GERMANY
| | - Maximillian Schütze
- Humboldt-Universität zu Berlin: Humboldt-Universitat zu Berlin Chemistry GERMANY
| | - Beatrice Cula
- Humboldt-Universität zu Berlin: Humboldt-Universitat zu Berlin Chemistry GERMANY
| | - Uwe Kuhlmann
- Technical University of Berlin: Technische Universitat Berlin Chemistry GERMANY
| | - Holger Dau
- FU Berlin: Freie Universitat Berlin Physics GERMANY
| | | | - Thomas Lohmiller
- Humboldt-Universität zu Berlin: Humboldt-Universitat zu Berlin Chemistry GERMANY
| | - Stefan Mebs
- FU Berlin: Freie Universitat Berlin Physics GERMANY
| | - Ulf-Peter Apfel
- Ruhr University Bochum: Ruhr-Universitat Bochum Faculty of Chemistry and Biochemistry GERMANY
| | - Kallol Ray
- Humboldt university Institute of chemistry Brook-taylor strasse 2 12489 Berlin GERMANY
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7
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Schmucker J, Fach A, Osteresch R, Mata Marin LA, Retzlaff T, Rühle S, Garstka D, Kuhlmann U, Eitel I, Hambrecht R, Wienbergen H. Temporal trends in treatment strategies and clinical outcomes among patients with advanced chronic kidney disease and ST-elevation myocardial infarctions: results from the Bremen STEMI registry. BMC Cardiovasc Disord 2022; 22:142. [PMID: 35365074 PMCID: PMC8976374 DOI: 10.1186/s12872-022-02573-1] [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] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 03/11/2022] [Indexed: 11/13/2022] Open
Abstract
Background Although the detrimental effects of advanced chronic kidney disease (CKD) on prognosis in coronary artery disease is known, there are few data on the efficacy and safety of modern interventional therapies and medications in patients with advanced CKD, because this special patient cohort is often excluded or underrepresented in randomized trials. Methods In the present study all patients admitted with ST-elevation myocardial infarctions (STEMI) from the region of Bremen/Germany treated between 2006 and 2019 were analyzed. Advanced CKD was defined as glomerular filtration rate < 45 ml/min.
Results Of 9605 STEMI-patients, 1018 (10.6%) had advanced CKD with a serum creatinine of 2.22 ± 4.2 mg/dl at admission and with lower rates of primary percutaneous coronary intervention (pPCI) (84.1 vs. 94.1%, p < 0.01) and higher all-cause-mortality (44.4 vs. 3.6%, p < 0.01). Over time, advanced CKD-patients were more likely to be treated with pPCI (2015–2019: 90.3% vs. 2006–2010:75.8%, p < 0.01) and with ticagrelor/prasugrel (59.6% vs. 1.7%, p < 0.01) and drug eluting stents (90.7% vs. 1.3%, p < 0.01). During the study period a decline in adverse ischemic events (OR 0.3, 95% CI 0.1–0.7) and an increase in bleedings (OR 2.2, 95% CI 1.3–3.8) within 1 year after the index event could be observed in patients with advanced CKD while 1-year-mortality (OR 1.0, 95% CI 0.7–1.4) and rates of acute kidney injury (OR 1.2, 95% CI 0.8–1.7) did not change in a multivariate model. Both, ticagrelor/prasugrel (OR 0.48, 95% CI 0.2–0.98) and DES (OR 0.38, 95% CI 0.2–0.8) were associated with a decrease in ischemic events at 1 year. Conclusions During the observed time period STEMI-patients with advanced CKD were more likely to be treated with primary PCI, ticagrelor or prasugrel and DE-stents. These changes probably have contributed to the decline in ischemic events and the increase in bleedings within 1 year after STEMI while overall mortality at 1-year remained unchanged for this high-risk patient group.
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Affiliation(s)
- Johannes Schmucker
- From the Bremen Institute for Heart and Circulation Research, am Klinikum Links der Weser, Senator-Weßling-Str. 1, 28277, Bremen, Germany. .,Medical Clinic III, Department of Nephrology and Cardiology, Klinikum Bremen Mitte, Bremen, Germany.
| | - Andreas Fach
- From the Bremen Institute for Heart and Circulation Research, am Klinikum Links der Weser, Senator-Weßling-Str. 1, 28277, Bremen, Germany
| | - Rico Osteresch
- From the Bremen Institute for Heart and Circulation Research, am Klinikum Links der Weser, Senator-Weßling-Str. 1, 28277, Bremen, Germany
| | - Luis Alberto Mata Marin
- From the Bremen Institute for Heart and Circulation Research, am Klinikum Links der Weser, Senator-Weßling-Str. 1, 28277, Bremen, Germany
| | - Tina Retzlaff
- From the Bremen Institute for Heart and Circulation Research, am Klinikum Links der Weser, Senator-Weßling-Str. 1, 28277, Bremen, Germany
| | - Stephan Rühle
- From the Bremen Institute for Heart and Circulation Research, am Klinikum Links der Weser, Senator-Weßling-Str. 1, 28277, Bremen, Germany
| | - Daniela Garstka
- From the Bremen Institute for Heart and Circulation Research, am Klinikum Links der Weser, Senator-Weßling-Str. 1, 28277, Bremen, Germany
| | - Uwe Kuhlmann
- Medical Clinic III, Department of Nephrology and Cardiology, Klinikum Bremen Mitte, Bremen, Germany
| | - Ingo Eitel
- Medical Clinic II, University Heart Center, Lübeck, Germany
| | - Rainer Hambrecht
- From the Bremen Institute for Heart and Circulation Research, am Klinikum Links der Weser, Senator-Weßling-Str. 1, 28277, Bremen, Germany
| | - Harm Wienbergen
- From the Bremen Institute for Heart and Circulation Research, am Klinikum Links der Weser, Senator-Weßling-Str. 1, 28277, Bremen, Germany.,Medical Clinic II, University Heart Center, Lübeck, Germany
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8
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Battistella B, Warm K, Cula B, Lu B, Hildebrandt P, Kuhlmann U, Dau H, Mebs S, Ray K. The influence of secondary interactions on the [Ni(O 2)] + mediated aldehyde oxidation reactions. J Inorg Biochem 2021; 227:111668. [PMID: 34923388 DOI: 10.1016/j.jinorgbio.2021.111668] [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] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 11/14/2021] [Accepted: 11/14/2021] [Indexed: 11/30/2022]
Abstract
A rate enhancement of one to two orders of magnitude can be obtained in the aldehyde deformylation reactions by replacing the -N(CH3) groups of [NiIII(O2)(Me4[12]aneN4)]+ (Me4[12]aneN4 = 1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane) and [NiIII(O2)(Me4[13]aneN4)]+ (Me4[13]aneN4 = 1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclotridecane) complexes by -NH in [NiIII(O2)([12]aneN4)]+ (2; [12]aneN4 = 1,4,7,10-tetraazacyclododecane) and [NiIII(O2)([13]aneN4)]+ (4; [13]aneN4 = 1,4,7,10-tetraazacyclotridecane). Based on detailed spectroscopic, reaction-kinetics and theoretical investigations, the higher reactivities of 2 and 4 are attributed to the changes in the secondary-sphere interactions between the [NiIII(O2)]+ and [12]aneN4 or [13]aneN4 moieties, which open up an alternative electrophilic pathway for the aldehyde oxidation reaction. Identification of primary kinetic isotope effects on the reactivity and stability of 2 when the -NH groups of the [12]aneN4 ligand are deuterated may also suggest the presence of secondary interaction between the -NH groups of [12]aneN4 and [NiIII(O2)]+ moieties, although, such interactions are not obvious in the DFT calculated optimized structure at the employed level of theory.
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Affiliation(s)
- Beatrice Battistella
- Humboldt-Universität zu Berlin, Institut für Chemie, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Katrin Warm
- Humboldt-Universität zu Berlin, Institut für Chemie, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Beatrice Cula
- Humboldt-Universität zu Berlin, Institut für Chemie, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Bernd Lu
- Humboldt-Universität zu Berlin, Institut für Chemie, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Peter Hildebrandt
- Technische Universität Berlin, Institut für Chemie, Sekretariat PC 14, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Uwe Kuhlmann
- Technische Universität Berlin, Institut für Chemie, Sekretariat PC 14, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Holger Dau
- Freie Universität zu Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Stefan Mebs
- Freie Universität zu Berlin, Fachbereich Physik, Arnimallee 14, 14195 Berlin, Germany
| | - Kallol Ray
- Humboldt-Universität zu Berlin, Institut für Chemie, Brook-Taylor-Straße 2, 12489 Berlin, Germany.
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9
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Warm K, Tripodi G, Andris E, Mebs S, Kuhlmann U, Dau H, Hildebrandt P, Roithová J, Ray K. Spektroskopische Charakterisierung eines reaktiven [Cu
2
(μ‐OH)
2
]
2+
Intermediates in Cu/TEMPO‐katalysierten aeroben Alkoholoxidationen. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202108442] [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: 11/06/2022]
Affiliation(s)
- Katrin Warm
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Deutschland
| | | | - Erik Andris
- Radboud University Heyendaalseweg 135 6525 AJ Nijmegen Niederlande
- Institute of Organic Chemistry and Biochemistry Czech Academy of Sciences Flemingovo náměstí 2 16610 Prague Czech Republic
| | - Stefan Mebs
- Institut für Physik Freie Universität Berlin Arnimallee 14 14195 Berlin Deutschland
| | - Uwe Kuhlmann
- Institut für Chemie, Fakultät II Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Deutschland
| | - Holger Dau
- Institut für Physik Freie Universität Berlin Arnimallee 14 14195 Berlin Deutschland
| | - Peter Hildebrandt
- Institut für Chemie, Fakultät II Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Deutschland
| | - Jana Roithová
- Radboud University Heyendaalseweg 135 6525 AJ Nijmegen Niederlande
| | - Kallol Ray
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Deutschland
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10
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Warm K, Tripodi G, Andris E, Mebs S, Kuhlmann U, Dau H, Hildebrandt P, Roithová J, Ray K. Spectroscopic Characterization of a Reactive [Cu 2 (μ-OH) 2 ] 2+ Intermediate in Cu/TEMPO Catalyzed Aerobic Alcohol Oxidation Reaction. Angew Chem Int Ed Engl 2021; 60:23018-23024. [PMID: 34309168 PMCID: PMC8518518 DOI: 10.1002/anie.202108442] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [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: 06/24/2021] [Revised: 07/16/2021] [Indexed: 12/23/2022]
Abstract
CuI/TEMPO (TEMPO=2,2,6,6‐tetramethylpiperidinyloxyl) catalyst systems are versatile catalysts for aerobic alcohol oxidation reactions to selectively yield aldehydes. However, several aspects of the mechanism are yet unresolved, mainly because of the lack of identification of any reactive intermediates. Herein, we report the synthesis and characterization of a dinuclear [L12Cu2]2+ complex 1, which in presence of TEMPO can couple the catalytic 4 H+/4 e− reduction of O2 to water to the oxidation of benzylic and aliphatic alcohols. The mechanisms of the O2‐reduction and alcohol oxidation reactions have been clarified by the spectroscopic detection of the reactive intermediates in the gas and condensed phases, as well as by kinetic studies on each step in the catalytic cycles. Bis(μ‐oxo)dicopper(III) (2) and bis(μ‐hydroxo)dicopper(II) species 3 are shown as viable reactants in oxidation catalysis. The present study provides deep mechanistic insight into the aerobic oxidation of alcohols that should serve as a valuable foundation for ongoing efforts dedicated towards the understanding of transition‐metal catalysts involving redox‐active organic cocatalysts.
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Affiliation(s)
- Katrin Warm
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Guilherme Tripodi
- Radboud University, Heyendaalseweg 135, 6525, AJ, Nijmegen, Netherlands
| | - Erik Andris
- Radboud University, Heyendaalseweg 135, 6525, AJ, Nijmegen, Netherlands.,Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo náměstí 2, 16610, Prague, Czech Republic
| | - Stefan Mebs
- Institut für Physik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Uwe Kuhlmann
- Institut für Chemie, Fakultät II, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Holger Dau
- Institut für Physik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany
| | - Peter Hildebrandt
- Institut für Chemie, Fakultät II, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Jana Roithová
- Radboud University, Heyendaalseweg 135, 6525, AJ, Nijmegen, Netherlands
| | - Kallol Ray
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
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11
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Warm K, Monte Pérez I, Kuhlmann U, Hildebrandt P, Farquhar E, Swart M, Ray K. Stable, but still reactive – investigations on the effects of Lewis acid binding on copper nitrene intermediates. Z Anorg Allg Chem 2021. [DOI: 10.1002/zaac.202100092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Katrin Warm
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Inés Monte Pérez
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Uwe Kuhlmann
- Institut für Chemie Technische Universität Berlin Fakultät II Straße des 17. Juni 135 10623 Berlin Germany
| | - Peter Hildebrandt
- Institut für Chemie Technische Universität Berlin Fakultät II Straße des 17. Juni 135 10623 Berlin Germany
| | - Erik Farquhar
- Brookhaven National Laboratory NSLS-II, Bldg. 745, Room 106, P.O. Box 5000 11973-5000 Upton NY United States
| | - Marcel Swart
- Institut de Química Computacional i Catàlisi Universitat de Girona Campus Montilivi (Ciències) Maria Aurèlia Capmany i Farnés, 69 17003 Girona, ICREA and Pg. Lluís Companys 23 08010 Barcelona Spain
| | - Kallol Ray
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
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12
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Deutscher J, Gerschel P, Warm K, Kuhlmann U, Mebs S, Haumann M, Dau H, Hildebrandt P, Apfel UP, Ray K. A bioinspired oxoiron(IV) motif supported on a N 2S 2 macrocyclic ligand. Chem Commun (Camb) 2021; 57:2947-2950. [PMID: 33621306 DOI: 10.1039/d1cc00250c] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A mononuclear oxoiron(iv) complex 1-trans bearing two equatorial sulfur ligations is synthesized and characterized as an active-site model of the elusive sulfur-ligated FeIV[double bond, length as m-dash]O intermediates in non-heme iron oxygenases. The introduction of sulfur ligands weakens the Fe[double bond, length as m-dash]O bond and enhances the oxidative reactivity of the FeIV[double bond, length as m-dash]O unit with a diminished deuterium kinetic isotope effect, thereby providing a compelling rationale for nature's use of the cis-thiolate ligated oxoiron(iv) motif in key metabolic transformations.
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Affiliation(s)
- Jennifer Deutscher
- Institut für Chemie Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489, Berlin, Germany.
| | - Philipp Gerschel
- Anorganische Chemie 1 Ruhr-Universität Bochum, Universitätsstraße 150, 44780, Bochum, Germany
| | - Katrin Warm
- Institut für Chemie Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489, Berlin, Germany.
| | - Uwe Kuhlmann
- Institut für Chemie Technische, Universität Berlin, Fakultät II Straße des 17, Juni 135, 10623, Berlin, Germany
| | - Stefan Mebs
- Institut für Physik Freie, Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Michael Haumann
- Institut für Physik Freie, Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Holger Dau
- Institut für Physik Freie, Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Peter Hildebrandt
- Institut für Chemie Technische, Universität Berlin, Fakultät II Straße des 17, Juni 135, 10623, Berlin, Germany
| | - Ulf-Peter Apfel
- Anorganische Chemie 1 Ruhr-Universität Bochum, Universitätsstraße 150, 44780, Bochum, Germany and Department of Electrosynthesis, Fraunhofer UMSICHT, Osterfelder Str. 3, 46047 Oberhausen, Germany
| | - Kallol Ray
- Institut für Chemie Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489, Berlin, Germany.
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13
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Warm K, Paskin A, Kuhlmann U, Bill E, Swart M, Haumann M, Dau H, Hildebrandt P, Ray K. A Pseudotetrahedral Terminal Oxoiron(IV) Complex: Mechanistic Promiscuity in C-H Bond Oxidation Reactions. Angew Chem Int Ed Engl 2021; 60:6752-6756. [PMID: 33348460 PMCID: PMC7985879 DOI: 10.1002/anie.202015896] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [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: 11/29/2020] [Indexed: 11/12/2022]
Abstract
S=2 oxoiron(IV) species act as reactive intermediates in the catalytic cycle of nonheme iron oxygenases. The few available synthetic S=2 FeIV =O complexes known to date are often limited to trigonal bipyramidal and very rarely to octahedral geometries. Herein we describe the generation and characterization of an S=2 pseudotetrahedral FeIV =O complex 2 supported by the sterically demanding 1,4,7-tri-tert-butyl-1,4,7-triazacyclononane ligand. Complex 2 is a very potent oxidant in hydrogen atom abstraction (HAA) reactions with large non-classical deuterium kinetic isotope effects, suggesting hydrogen tunneling contributions. For sterically encumbered substrates, direct HAA is impeded and an alternative oxidative asynchronous proton-coupled electron transfer mechanism prevails, which is unique within the nonheme oxoiron community. The high reactivity and the similar spectroscopic parameters make 2 one of the best electronic and functional models for a biological oxoiron(IV) intermediate of taurine dioxygenase (TauD-J).
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Affiliation(s)
- Katrin Warm
- Institut für ChemieHumboldt-Universität zu BerlinBrook-Taylor-Str. 212489BerlinGermany
| | - Alice Paskin
- Institut für ChemieHumboldt-Universität zu BerlinBrook-Taylor-Str. 212489BerlinGermany
| | - Uwe Kuhlmann
- Institut für ChemieTechnische Universität Berlin, Fakultät IIStraße des 17. Juni 13510623BerlinGermany
| | - Eckhard Bill
- Max-Planck-Institut für Chemische Energiekonversion (CEC)Stiftstraße 34–3645470MülheimGermany
| | - Marcel Swart
- Institut de Química Computacional i CatàlisiUniversitat de GironaCampus Montilivi (Ciències)Maria Aurèlia Capmany i Farnés, 6917003GironaSpain
- ICREAPg. Lluís Companys 2308010BarcelonaSpain
| | - Michael Haumann
- Institut für PhysikFreie Universität BerlinArnimallee 1414195BerlinGermany
| | - Holger Dau
- Institut für PhysikFreie Universität BerlinArnimallee 1414195BerlinGermany
| | - Peter Hildebrandt
- Institut für ChemieTechnische Universität Berlin, Fakultät IIStraße des 17. Juni 13510623BerlinGermany
| | - Kallol Ray
- Institut für ChemieHumboldt-Universität zu BerlinBrook-Taylor-Str. 212489BerlinGermany
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14
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Warm K, Paskin A, Kuhlmann U, Bill E, Swart M, Haumann M, Dau H, Hildebrandt P, Ray K. A Pseudotetrahedral Terminal Oxoiron(IV) Complex: Mechanistic Promiscuity in C−H Bond Oxidation Reactions. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202015896] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Katrin Warm
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Str. 2 12489 Berlin Germany
| | - Alice Paskin
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Str. 2 12489 Berlin Germany
| | - Uwe Kuhlmann
- Institut für Chemie Technische Universität Berlin, Fakultät II Straße des 17. Juni 135 10623 Berlin Germany
| | - Eckhard Bill
- Max-Planck-Institut für Chemische Energiekonversion (CEC) Stiftstraße 34–36 45470 Mülheim Germany
| | - Marcel Swart
- Institut de Química Computacional i Catàlisi Universitat de Girona Campus Montilivi (Ciències) Maria Aurèlia Capmany i Farnés, 69 17003 Girona Spain
- ICREA Pg. Lluís Companys 23 08010 Barcelona Spain
| | - Michael Haumann
- Institut für Physik Freie Universität Berlin Arnimallee 14 14195 Berlin Germany
| | - Holger Dau
- Institut für Physik Freie Universität Berlin Arnimallee 14 14195 Berlin Germany
| | - Peter Hildebrandt
- Institut für Chemie Technische Universität Berlin, Fakultät II Straße des 17. Juni 135 10623 Berlin Germany
| | - Kallol Ray
- Institut für Chemie Humboldt-Universität zu Berlin Brook-Taylor-Str. 2 12489 Berlin Germany
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15
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Rauen T, Wied S, Fitzner C, Eitner F, Sommerer C, Zeier M, Otte B, Panzer U, Budde K, Benck U, Mertens PR, Kuhlmann U, Witzke O, Gross O, Vielhauer V, Mann JFE, Hilgers RD, Floege J. After ten years of follow-up, no difference between supportive care plus immunosuppression and supportive care alone in IgA nephropathy. Kidney Int 2020; 98:1044-1052. [PMID: 32450154 DOI: 10.1016/j.kint.2020.04.046] [Citation(s) in RCA: 91] [Impact Index Per Article: 22.8] [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: 02/05/2020] [Revised: 04/03/2020] [Accepted: 04/16/2020] [Indexed: 12/22/2022]
Abstract
The randomized, controlled STOP-IgAN trial in patients with IgA nephropathy (IgAN) and substantial proteinuria showed no benefit of immunosuppression added on top of supportive care on renal function over three years. As a follow-up we evaluated renal outcomes in patients over a follow-up of up to ten years in terms of serum creatinine, proteinuria, end-stage kidney disease (ESKD), and death. The adapted primary endpoint was the time to first occurrence of a composite of death, ESKD, or a decline of over 40% in the estimated glomerular filtration rate (eGFR) compared to baseline at randomization into STOP-IgAN. Data were analyzed by Cox-regression models. Follow-up data were available for 149 participants, representing 92% of the patients originally randomized. Median follow-up was 7.4 years (inter quartile range 5.7 to 8.3 years). The primary endpoint was reached in 36 of 72 patients randomized to supportive care and 35 of 77 patients randomized to additional immunosuppression (hazard ratio 1.20; 95% confidence interval 0.75 to 1.92). ESKD occurred in 17 of the patients with supportive care and in 20 of the patients with additional immunosuppression. Additionally, the rates of eGFR loss over 40% and annual eGFR loss did not differ between groups. Two patients died with supportive care and three with additional immunosuppression. Thus, within the limitations of a retrospective study, over a follow-up of up to ten years, and using an adapted primary endpoint, we failed to detect differences in key clinical outcomes in IgAN patients randomized to receive added immunosuppression on top of supportive care versus supportive care alone.
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Affiliation(s)
- Thomas Rauen
- Division of Nephrology and Clinical Immunology, RWTH Aachen University, Aachen, Germany
| | - Stephanie Wied
- Department of Medical Statistics, RWTH Aachen University, Aachen, Germany
| | - Christina Fitzner
- Department of Medical Statistics, RWTH Aachen University, Aachen, Germany
| | - Frank Eitner
- Division of Nephrology and Clinical Immunology, RWTH Aachen University, Aachen, Germany; Bayer AG, Kidney Diseases Research, Wuppertal, Germany
| | - Claudia Sommerer
- Department of Nephrology and Renal Center Heidelberg, University of Heidelberg, Heidelberg, Germany
| | - Martin Zeier
- Department of Nephrology and Renal Center Heidelberg, University of Heidelberg, Heidelberg, Germany
| | - Britta Otte
- Internal Medicine D, Department of Nephrology, Hypertension and Rheumatology, University Hospital Muenster, Muenster, Germany
| | - Ulf Panzer
- Division of Nephrology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Klemens Budde
- Department of Nephrology, Charité Campus Mitte, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Urs Benck
- Department of Medicine V, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany
| | - Peter R Mertens
- Department of Nephrology and Hypertension, Diabetes and Endocrinology, Otto-von-Guericke University, Magdeburg, Germany
| | - Uwe Kuhlmann
- Medical Clinic III, Central Hospital Bremen, Bremen, Germany
| | - Oliver Witzke
- Department of Infectious Diseases, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Oliver Gross
- Clinic for Nephrology and Rheumatology, University Medical Center Goettingen, Goettingen, Germany
| | - Volker Vielhauer
- Nephrologisches Zentrum, Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, LMU München, Munich, Germany
| | - Johannes F E Mann
- KfH Kidney Center Munich-Schwabing and Department of Medicine IV, University of Erlangen, Erlangen, Germany
| | | | - Jürgen Floege
- Division of Nephrology and Clinical Immunology, RWTH Aachen University, Aachen, Germany.
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16
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Chandra A, Mebs S, Kundu S, Kuhlmann U, Hildebrandt P, Dau H, Ray K. Catalytic dioxygen reduction mediated by a tetranuclear cobalt complex supported on a stannoxane core. Dalton Trans 2020; 49:6065-6073. [PMID: 32319492 DOI: 10.1039/d0dt00475h] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The synthesis, spectroscopic characterization (infrared, electron paramagnetic resonance and X-ray absorption spectroscopies) and density functional theoretical calculations of a tetranuclear cobalt complex Co4L1 involving a nonheme ligand system, L1, supported on a stannoxane core are reported. Co4L1, similar to the previously reported hexanuclear cobalt complex Co6L2, shows a unique ability to catalyze dioxygen (O2) reduction, where product selectivity can be changed from a preferential 4e-/4H+ dioxygen-reduction (to water) to a 2e-/2H+ process (to hydrogen peroxide) only by increasing the temperature from -50 to 30 °C. Detailed mechanistic insights were obtained on the basis of kinetic studies on the overall catalytic reaction as well as by low-temperature spectroscopic (UV-Vis, resonance Raman and X-ray absorption spectroscopies) trapping of the end-on μ-1,2-peroxodicobalt(iii) intermediate 1. The Co4L1- and Co6L2-mediated O2-reduction reactions exhibit different reaction kinetics, and yield different ratios of the 2e-/2H+ and 4e-/4H+ products at -50 °C, which can be attributed to the different stabilities of the μ-1,2-peroxodicobalt(iii) intermediates formed upon dioxygen activation in the two cases. The deep mechanistic insights into the transition-metal mediated dioxygen reduction process that are obtained from the present study should serve as useful and broadly applicable principles for future design of more efficient catalysts in fuel cells.
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Affiliation(s)
- Anirban Chandra
- Humboldt-Universität zu Berlin, Institut für Chemie, Brook-Taylor-Straße 2, D-12489 Berlin, Germany.
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17
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Kass D, Corona T, Warm K, Braun-Cula B, Kuhlmann U, Bill E, Mebs S, Swart M, Dau H, Haumann M, Hildebrandt P, Ray K. Stoichiometric Formation of an Oxoiron(IV) Complex by a Soluble Methane Monooxygenase Type Activation of O 2 at an Iron(II)-Cyclam Center. J Am Chem Soc 2020; 142:5924-5928. [PMID: 32168447 DOI: 10.1021/jacs.9b13756] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In soluble methane monooxygenase enzymes (sMMO), dioxygen (O2) is activated at a diiron(II) center to form an oxodiiron(IV) intermediate Q that performs the challenging oxidation of methane to methanol. An analogous mechanism of O2 activation at mono- or dinuclear iron centers is rare in the synthetic chemistry. Herein, we report a mononuclear non-heme iron(II)-cyclam complex, 1-trans, that activates O2 to form the corresponding iron(IV)-oxo complex, 2-trans, via a mechanism reminiscent of the O2 activation process in sMMO. The conversion of 1-trans to 2-trans proceeds via the intermediate formation of an iron(III)-superoxide species 3, which could be trapped and spectroscopically characterized at -50 °C. Surprisingly, 3 is a stronger oxygen atom transfer (OAT) agent than 2-trans; 3 performs OAT to 1-trans or PPh3 to yield 2-trans quantitatively. Furthermore, 2-trans oxidizes the aromatic C-H bonds of 2,6-di-tert-butylphenol, which, together with the strong OAT ability of 3, represents new domains of oxoiron(IV) and superoxoiron(III) reactivities.
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Affiliation(s)
- Dustin Kass
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Teresa Corona
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Katrin Warm
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Beatrice Braun-Cula
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
| | - Uwe Kuhlmann
- Department of Chemistry, Technische Universität Berlin, Straβe des 17. Juni 135, 10623 Berlin, Germany
| | - Eckhard Bill
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Stefan Mebs
- Department of Physics, Freie Universität Berlin, Arminallee 14, 14195 Berlin, Germany
| | - Marcel Swart
- ICREA, Lluis Companys 23, 08010 Barcelona, Spain.,IQCC, Universitat de Girona, Campus Montilivi, 17003 Girona, Spain
| | - Holger Dau
- Department of Physics, Freie Universität Berlin, Arminallee 14, 14195 Berlin, Germany
| | - Michael Haumann
- Department of Physics, Freie Universität Berlin, Arminallee 14, 14195 Berlin, Germany
| | - Peter Hildebrandt
- Department of Chemistry, Technische Universität Berlin, Straβe des 17. Juni 135, 10623 Berlin, Germany
| | - Kallol Ray
- Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
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18
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Affiliation(s)
- E. Hübel
- Robert-Bosch-Hospital Department of Internal Medicine Division of Nephrology Auerbachstr. 110 7000 Stuttgart West Germany
| | - M. Kanitz
- Robert-Bosch-Hospital Department of Internal Medicine Division of Nephrology Auerbachstr. 110 7000 Stuttgart West Germany
| | - U. Kuhlmann
- Robert-Bosch-Hospital Department of Internal Medicine Division of Nephrology Auerbachstr. 110 7000 Stuttgart West Germany
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19
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Affiliation(s)
- C. Pauli–Magnus
- Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, Department of Internal Medicine Robert-Bosch-Hospital Stuttgart Auerbachstrasse 110 70376 Stuttgart, Germany
| | - S. Klumpp
- Department of Pharmacy, Department of Internal Medicine Robert-Bosch-Hospital Stuttgart Auerbachstrasse 110 70376 Stuttgart, Germany
| | - D.M. Alscher
- Division of Nephrology, Department of Internal Medicine Robert-Bosch-Hospital Stuttgart Auerbachstrasse 110 70376 Stuttgart, Germany
| | - U. Kuhlmann
- Division of Nephrology, Department of Internal Medicine Robert-Bosch-Hospital Stuttgart Auerbachstrasse 110 70376 Stuttgart, Germany
| | - T. Mettang
- Division of Nephrology, Department of Internal Medicine Robert-Bosch-Hospital Stuttgart Auerbachstrasse 110 70376 Stuttgart, Germany
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20
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Kuhlmann U, Maierhofer A, Canaud B, Hoyer J, Gross M. Zero Diffusive Sodium Balance in Hemodialysis Provided by an Algorithm‐Based Electrolyte Balancing Controller: A Proof of Principle Clinical Study. Artif Organs 2018; 43:150-158. [DOI: 10.1111/aor.13328] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 06/28/2018] [Accepted: 07/02/2018] [Indexed: 12/15/2022]
Affiliation(s)
- Uwe Kuhlmann
- Klinikum Bremen Mitte Medizinische Klinik III Bremen Germany
| | | | | | - Joachim Hoyer
- Universitätsklinik Marburg Klinik für Innere Medizin, Nephrologie und Internistische Intensivmedizin Marburg Germany
| | - Malte Gross
- Faculty of Mechatronics and Medical Technology Ulm University of Applied Sciences Ulm Germany
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Abstract
The control of intravascular volume (IVV) by continuous on-line measurement of protein concentration would optimise the patients’ specific rate of ultrafiltration. To prove the accuracy of a refractometric device, plasma was continuously drawn by haemofiltration during 10 haemodialysis treatments of male patients. Refractometry reflects highly significant changes in the concentrations of filtrate proteins (r = 0.862, p < 0.001) and blood proteins (rtotal = 0.593, ptotal < 0.001). In vitro, the refractometric device detected a change of protein concentration of 0.041 g/L through a refraction increase of 0.1 mV. The power of discrimination was 0.067 % of IVV. However, in vivo, the accuracy of IVV refractometric monitoring is reduced by interference factors such as sodium (0.141 mV/mmol/L), glucose (0.034 mV/mg/dl) and triglycerides (–0.040 mV/mg/dl). Adjustment of the refraction data using sodium and glucose electrodes and plasma filters with a cutoff below the size of chylomicrons is recommended.
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Affiliation(s)
- U. Kuhlmann
- Department of Nephrology and Pathol. Physiol., Dept. Appl. Physiol. Philipps University of Marburg, Marburg - Germany
| | - F. V. Buuren
- Department of Nephrology and Pathol. Physiol., Dept. Appl. Physiol. Philipps University of Marburg, Marburg - Germany
| | - O. Aziz
- Institute of Normal and Pathol. Physiol., Dept. Appl. Physiol. Philipps University of Marburg, Marburg - Germany
| | - H. Lange
- Department of Nephrology and Pathol. Physiol., Dept. Appl. Physiol. Philipps University of Marburg, Marburg - Germany
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22
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Kuhlmann U, Gräf R, Schindler J, Lange H. Continuous Ionography (CIG) in Haemodialysis by Ion-Selective Carrier Membrane Electrodes (ISCME) with Solid Cement Contact for Flow-Through Measurement. Int J Artif Organs 2018. [DOI: 10.1177/039139889201500404] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Ion balance is of particular interest for patients maintained on RDT because of the importance of controlling ion movement and ion removal during haemodialysis. Continuous ionography (CIG) was therefore tested for electrolyte monitoring in extracorporeal haemodialysis in vitro and in vivo. The accuracy and stability of the electrodes were examined and various concentrations of potassium in blood, ultrafiltrate and dialysate were evaluated. Ion selective carrier membrane electrodes (ISCME) appeared to be suitable for continuous and simultaneous measurement of ions in blood and dialysis fluid. CIG monitoring of ion movement and ion removal could be the basis for adjusting and computer-managing ion elimination during extracorporeal haemodialysis.
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Affiliation(s)
- U. Kuhlmann
- Department of Nephrology University of Marburg - Germany
| | - R. Gräf
- Department of Nephrology University of Marburg - Germany
| | - J. Schindler
- Institute of Normal and Pathological Physiology, Dept. of Applied Physiology, University of Marburg - Germany
| | - H. Lange
- Department of Nephrology University of Marburg - Germany
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23
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Risler T, Braun N, Hanel K, Kuhlmann U, Skroch D, Müller G. Do Different Dialysis-Membranes Affect Beta 2-Microglobulin Kinetics during Chronic Hemodialysis? Int J Artif Organs 2018. [DOI: 10.1177/039139889401701105] [Citation(s) in RCA: 5] [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: 11/17/2022]
Abstract
Hemodialysis is not an absolute prerequisite for the formation of β2-microglobulin amyloidosis, but it enhances the progression of this complication related to long-standing renal failure. Thus the clearance and turnover of β2-microglobulin seems to play a major role in this disease. In a prospective multicenter study the β2-microglobulin clearance was studied in 87 patients starting hemodialysis. Serum samples were taken prior to and after the first dialysis session and also before and after dialysis at 4, 6, 12, 16, 26 and 52 weeks. Patients were either treated by cuprophane or a polyacrylonitril membrane. At the start, the mean serum β2-microglobulin level was about 18 mg/L in patients treated with a cuprophane membrane, but the levels increased after hemodialysis and reached a plateau, which was always higher than in those treated with polyacrylonitril, which cleared β2-microglobulin from the serum. However, after 12 months the difference was no longer significant. Thus β2-microglobulin excretion during dialysis differs between the two membranes, but seems to lose its significance for the β2-microglobulin serum level in chronic hemodialysis treatment.
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Affiliation(s)
- T. Risler
- Section of Nephrology and Hypertension, Dept. of Medicine, University Hospital Tübingen, Tübingen
| | - N. Braun
- Section of Nephrology and Hypertension, Dept. of Medicine, University Hospital Tübingen, Tübingen
| | - K.D. Hanel
- Division of Nephrology, Klinikum am Eichert, Göppingen
| | - U. Kuhlmann
- Department of Nephrology, Robert-Bosch-Hospital, Stuttgart
| | | | - G.A. Müller
- Section of Nephrology and Hypertension, Dept. of Medicine, University Hospital Tübingen, Tübingen
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24
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Buhrke D, Kuhlmann U, Michael N, Hildebrandt P. The Photoconversion of Phytochrome Includes an Unproductive Shunt Reaction Pathway. Chemphyschem 2018; 19:566-570. [DOI: 10.1002/cphc.201701311] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Indexed: 11/08/2022]
Affiliation(s)
- David Buhrke
- Institut für Chemie, Sekr. PC14; Technische Universität Berlin; Straße des 17. Juni 135 10623 Berlin Germany
| | - Uwe Kuhlmann
- Institut für Chemie, Sekr. PC14; Technische Universität Berlin; Straße des 17. Juni 135 10623 Berlin Germany
| | - Norbert Michael
- Institut für Chemie, Sekr. PC14; Technische Universität Berlin; Straße des 17. Juni 135 10623 Berlin Germany
| | - Peter Hildebrandt
- Institut für Chemie, Sekr. PC14; Technische Universität Berlin; Straße des 17. Juni 135 10623 Berlin Germany
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25
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Rauen T, Fitzner C, Eitner F, Sommerer C, Zeier M, Otte B, Panzer U, Peters H, Benck U, Mertens PR, Kuhlmann U, Witzke O, Gross O, Vielhauer V, Mann JFE, Hilgers RD, Floege J. Effects of Two Immunosuppressive Treatment Protocols for IgA Nephropathy. J Am Soc Nephrol 2017; 29:317-325. [PMID: 29042456 DOI: 10.1681/asn.2017060713] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [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: 06/30/2017] [Accepted: 09/14/2017] [Indexed: 11/03/2022] Open
Abstract
The role of immunosuppression in IgA nephropathy (IgAN) is controversial. In the Supportive Versus Immunosuppressive Therapy for the Treatment of Progressive IgA Nephropathy (STOP-IgAN) Trial, 162 patients with IgAN and proteinuria >0.75 g/d after 6 months of optimized supportive care were randomized into two groups: continued supportive care or additional immunosuppression (GFR≥60 ml/min per 1.73 m2: 6-month corticosteroid monotherapy; GFR=30-59 ml/min per 1.73 m2: cyclophosphamide for 3 months followed by azathioprine plus oral prednisolone). Coprimary end points were full clinical remission and GFR loss ≥15 ml/min per 1.73 m2 during the 3-year trial phase. In this secondary intention to treat analysis, we separately analyzed data from each immunosuppression subgroup and the corresponding patients on supportive care. Full clinical remission occurred in 11 (20%) patients receiving corticosteroid monotherapy and three (6%) patients on supportive care (odds ratio, 5.31; 95% confidence interval, 1.07 to 26.36; P=0.02), but the rate did not differ between patients receiving immunosuppressive combination and controls on supportive care (11% versus 4%, respectively; P=0.30). The end point of GFR loss ≥15 ml/min per 1.73 m2 did not differ between groups. Only corticosteroid monotherapy transiently reduced proteinuria at 12 months. Severe infections, impaired glucose tolerance, and/or weight gain in the first year were more frequent with either immunosuppressive regimen than with supportive care. In conclusion, only corticosteroid monotherapy induced disease remission in a minority of patients who had IgAN with relatively well preserved GFR and persistent proteinuria. Neither immunosuppressive regimen prevented GFR loss, and both associated with substantial adverse events.
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Affiliation(s)
- Thomas Rauen
- Division of Nephrology and Clinical Immunology and
| | - Christina Fitzner
- Department of Medical Statistics, RWTH Aachen University, Aachen, Germany
| | - Frank Eitner
- Division of Nephrology and Clinical Immunology and.,Kidney Diseases Research, Bayer AG, Wuppertal, Germany
| | - Claudia Sommerer
- Department of Nephrology, University of Heidelberg, Heidelberg, Germany
| | - Martin Zeier
- Department of Nephrology, University of Heidelberg, Heidelberg, Germany
| | - Britta Otte
- Internal Medicine D, Department of Nephrology, Hypertension and Rheumatology, University Hospital Muenster, Muenster, Germany
| | - Ulf Panzer
- Medical Clinic, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Harm Peters
- Department of Nephrology and Intensive Care and.,Dieter Scheffner Center for Medical Education, Charité Campus Mitte, Charité-Universitaetsmedizin Berlin, Berlin, Germany
| | - Urs Benck
- Department of Medicine V, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany
| | - Peter R Mertens
- Department of Nephrology and Hypertension, Diabetes and Endocrinology, Otto von Guericke University, Magdeburg, Germany
| | - Uwe Kuhlmann
- Medical Clinic III, Central Hospital Bremen, Bremen, Germany
| | - Oliver Witzke
- Departments of Infectious Diseases and.,Nephrology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Oliver Gross
- Clinic for Nephrology and Rheumatology, University Medical Center Goettingen, Goettingen, Germany
| | - Volker Vielhauer
- Nephrologisches Zentrum, Medizinische Klinik und Poliklinik IV, Klinikum der Ludwig Maximilians Universität, Munich, Germany; and
| | - Johannes F E Mann
- Department of Nephrology, Hypertension and Rheumatology, Munich General Hospitals, Munich, Germany
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26
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Monte-Pérez I, Kundu S, Chandra A, Craigo KE, Chernev P, Kuhlmann U, Dau H, Hildebrandt P, Greco C, Van Stappen C, Lehnert N, Ray K. Temperature Dependence of the Catalytic Two- versus Four-Electron Reduction of Dioxygen by a Hexanuclear Cobalt Complex. J Am Chem Soc 2017; 139:15033-15042. [DOI: 10.1021/jacs.7b07127] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Inés Monte-Pérez
- Humboldt-Universität zu Berlin, Institut für Chemie, Brook-Taylor-Straße 2, D-12489 Berlin, Germany
| | - Subrata Kundu
- Humboldt-Universität zu Berlin, Institut für Chemie, Brook-Taylor-Straße 2, D-12489 Berlin, Germany
| | - Anirban Chandra
- Humboldt-Universität zu Berlin, Institut für Chemie, Brook-Taylor-Straße 2, D-12489 Berlin, Germany
| | - Kathryn E. Craigo
- Department
of Chemistry, The University of Michigan, 930 N. University Ave., Ann Arbor, Michigan 48109, United States
| | - Petko Chernev
- Freie Universität Berlin, FB Physik, Arnimallee 14, D-14195 Berlin, Germany
| | - Uwe Kuhlmann
- Department
of Chemistry, Technische Universität Berlin, Straße des
17. Juni 135, 10623 Berlin, Germany
| | - Holger Dau
- Freie Universität Berlin, FB Physik, Arnimallee 14, D-14195 Berlin, Germany
| | - Peter Hildebrandt
- Department
of Chemistry, Technische Universität Berlin, Straße des
17. Juni 135, 10623 Berlin, Germany
| | - Claudio Greco
- Department
of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza
della Scienza, 1, 20126 Milan, Italy
| | - Casey Van Stappen
- Department
of Chemistry, The University of Michigan, 930 N. University Ave., Ann Arbor, Michigan 48109, United States
| | - Nicolai Lehnert
- Department
of Chemistry, The University of Michigan, 930 N. University Ave., Ann Arbor, Michigan 48109, United States
| | - Kallol Ray
- Humboldt-Universität zu Berlin, Institut für Chemie, Brook-Taylor-Straße 2, D-12489 Berlin, Germany
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27
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Werther T, Wahlefeld S, Salewski J, Kuhlmann U, Zebger I, Hildebrandt P, Dobbek H. Redox-dependent substrate-cofactor interactions in the Michaelis-complex of a flavin-dependent oxidoreductase. Nat Commun 2017. [PMCID: PMC5519977 DOI: 10.1038/ncomms16084] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
How an enzyme activates its substrate for turnover is fundamental for catalysis but incompletely understood on a structural level. With redox enzymes one typically analyses structures of enzyme–substrate complexes in the unreactive oxidation state of the cofactor, assuming that the interaction between enzyme and substrate is independent of the cofactors oxidation state. Here, we investigate the Michaelis complex of the flavoenzyme xenobiotic reductase A with the reactive reduced cofactor bound to its substrates by X-ray crystallography and resonance Raman spectroscopy and compare it to the non-reactive oxidized Michaelis complex mimics. We find that substrates bind in different orientations to the oxidized and reduced flavin, in both cases flattening its structure. But only authentic Michaelis complexes display an unexpected rich vibrational band pattern uncovering a strong donor–acceptor complex between reduced flavin and substrate. This interaction likely activates the catalytic ground state of the reduced flavin, accelerating the reaction within a compressed cofactor–substrate complex. Due to their transient nature, enzyme-substrate complexes are difficult to characterize structurally. Here, the authors capture the reactive reduced form of xenobiotic reductase A bound to its substrate and show that the oxidation state of the flavin cofactor affects the interaction of the substrate with the enzyme.
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28
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Song W, Querebillo CJ, Götz R, Katz S, Kuhlmann U, Gernert U, Weidinger IM, Hildebrandt P. Reversible light-dependent molecular switches on Ag/AgCl nanostructures. Nanoscale 2017; 9:8380-8387. [PMID: 28594421 DOI: 10.1039/c7nr02760e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Nanostructured Ag/AgCl substrates were used to generate reversible and highly efficient light-dependent chemical switches based on adsorbed 4,4'-dimercaptoazobenzene (DMAB). DMAB was formed in situ via laser-induced dimerization either from 4-nitrothiophenol (4-NTP) or 4-aminothiophenol (4-ATP). The subsequent reaction pathways of DMAB, however, were quite different as monitored by surface enhanced Raman spectroscopy. In the 4-NTP/DMAB system, AgCl catalyses the reversal of the dimerization. Conversely, irradiation of adsorbed 4-ATP first generated cis-DMAB attached to the surface via two Ag-S bonds, followed by AgCl-catalysed cleavage of one Ag-S bond and cis → trans photoisomerisation of DMAB. In the dark, the trans-isomer thermally reverts to cis-DMAB. The here presented light-dark chemical switches, which work without changing other parameters (e.g., pH, anaerobic vs. aerobic), are based on the (photo)catalytic properties of the Ag/AgCl substrate and do not function on pure metal surfaces.
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Affiliation(s)
- W Song
- Technische Universität Berlin, Institut für Chemie, Sekr. PC 14, Strasse des 17. Juni 135, D-10623, Berlin, Germany.
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29
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Keidel A, López I, Staffa J, Kuhlmann U, Bozoglian F, Gimbert-Suriñach C, Benet-Buchholz J, Hildebrandt P, Llobet A. Electrochemical and Resonance Raman Spectroscopic Studies of Water-Oxidizing Ruthenium Terpyridyl-Bipyridyl Complexes. ChemSusChem 2017; 10:551-561. [PMID: 27863077 DOI: 10.1002/cssc.201601221] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Indexed: 06/06/2023]
Abstract
The irreversible conversion of single-site water-oxidation catalysts (WOC) into more rugged catalysts structurally related to [(trpy)(5,5'-X2 -bpy)RuIV (μ-O)RuIV (trpy)(O)(H2 O)]4+ (X=H, 1-dn4+ ; X=F, 2-dn4+ ; bpy=2,2'-bipyridine; trpy=2,2':6',2"-terpyridine) represents a critical issue in the development of active and durable WOCs. In this work, the electrochemical and acid-base properties of 1-dn4+ and 2-dn4+ were evaluated. In situ resonance Raman spectroscopy was employed to characterize the species formed upon the stoichiometric oxidation of the single-site catalysts and demonstrated the formation of high-oxidation-state mononuclear Ru=O and RuO-O complexes. Under turnover conditions, the dinuclear intermediates, 1-dn4+ and 2-dn4+ as well as the previously proposed [RuVI (trpy)(O)2 (H2 O)]2+ complex (32+ ) are formed. Complex 32+ is a pivotal intermediate that provides access to the formation of dinuclear species. Single-crystal X-ray diffraction analysis of the isolated complex [RuIV (O)(trpy)(5,5'-F2 -bpy)]2+ reveals a clear elongation of the Ru-N bond trans to the oxido ligand that documents the weakness of this bond, which promotes the release of the bpy ligand and the subsequent formation of 32+ .
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Affiliation(s)
- Anke Keidel
- Institut für Chemie, Technische Universität Berlin, Sekr. PC14, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Isidoro López
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Av. Països Catalans, 16, 43007, Tarragona, Spain
| | - Jana Staffa
- Institut für Chemie, Technische Universität Berlin, Sekr. PC14, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Uwe Kuhlmann
- Institut für Chemie, Technische Universität Berlin, Sekr. PC14, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Fernando Bozoglian
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Av. Països Catalans, 16, 43007, Tarragona, Spain
| | - Carolina Gimbert-Suriñach
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Av. Països Catalans, 16, 43007, Tarragona, Spain
| | - Jordi Benet-Buchholz
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Av. Països Catalans, 16, 43007, Tarragona, Spain
| | - Peter Hildebrandt
- Institut für Chemie, Technische Universität Berlin, Sekr. PC14, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Antoni Llobet
- Institute of Chemical Research of Catalonia (ICIQ), Barcelona Institute of Science and Technology (BIST), Av. Països Catalans, 16, 43007, Tarragona, Spain
- Departament de Química, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, 08193, Barcelona, Spain
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30
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Affiliation(s)
- Matthias Nacken
- Rheydt
- Institut für Eisenhüttenwesen der Rheinisch-Westfälischen Technischen Hochschule Aachen; Aachen
| | - Uwe Kuhlmann
- Rheydt
- Institut für Eisenhüttenwesen der Rheinisch-Westfälischen Technischen Hochschule Aachen; Aachen
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31
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Engelmann X, Yao S, Farquhar ER, Szilvási T, Kuhlmann U, Hildebrandt P, Driess M, Ray K. A New Domain of Reactivity for High-Valent Dinuclear [M(μ-O) 2 M'] Complexes in Oxidation Reactions. Angew Chem Int Ed Engl 2016; 56:297-301. [PMID: 27906528 DOI: 10.1002/anie.201607611] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [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: 08/05/2016] [Revised: 10/06/2016] [Indexed: 12/31/2022]
Abstract
The strikingly different reactivity of a series of homo- and heterodinuclear [(MIII )(μ-O)2 (MIII )']2+ (M=Ni; M'=Fe, Co, Ni and M=M'=Co) complexes with β-diketiminate ligands in electrophilic and nucleophilic oxidation reactions is reported, and can be correlated to the spectroscopic features of the [(MIII )(μ-O)2 (MIII )']2+ core. In particular, the unprecedented nucleophilic reactivity of the symmetric [NiIII (μ-O)2 NiIII ]2+ complex and the decay of the asymmetric [NiIII (μ-O)2 CoIII ]2+ core through aromatic hydroxylation reactions represent a new domain for high-valent bis(μ-oxido)dimetal reactivity.
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Affiliation(s)
- Xenia Engelmann
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
| | - Shenglai Yao
- Department of Chemistry, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Erik R Farquhar
- Case Center for Synchrotron Biosciences, NSLS-II, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Tibor Szilvási
- Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szent Gellért tér 4, 1111, Budapest, Hungary
| | - Uwe Kuhlmann
- Department of Chemistry, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Peter Hildebrandt
- Department of Chemistry, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Matthias Driess
- Department of Chemistry, Technische Universität Berlin, Straße des 17. Juni 135, 10623, Berlin, Germany
| | - Kallol Ray
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany
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32
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Engelmann X, Yao S, Farquhar ER, Szilvási T, Kuhlmann U, Hildebrandt P, Driess M, Ray K. A New Domain of Reactivity for High‐Valent Dinuclear [M(μ‐O)
2
M′] Complexes in Oxidation Reactions. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201607611] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Xenia Engelmann
- Department of Chemistry Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
| | - Shenglai Yao
- Department of Chemistry Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
| | - Erik R. Farquhar
- Case Center for Synchrotron Biosciences, NSLS-II Brookhaven National Laboratory Upton NY 11973 USA
| | - Tibor Szilvási
- Department of Inorganic and Analytical Chemistry Budapest University of Technology and Economics Szent Gellért tér 4 1111 Budapest Hungary
| | - Uwe Kuhlmann
- Department of Chemistry Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
| | - Peter Hildebrandt
- Department of Chemistry Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
| | - Matthias Driess
- Department of Chemistry Technische Universität Berlin Straße des 17. Juni 135 10623 Berlin Germany
| | - Kallol Ray
- Department of Chemistry Humboldt-Universität zu Berlin Brook-Taylor-Straße 2 12489 Berlin Germany
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33
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Luce R, Hildebrandt P, Kuhlmann U, Liesen J. Using Separable Nonnegative Matrix Factorization Techniques for the Analysis of Time-Resolved Raman Spectra. Appl Spectrosc 2016; 70:1464-1475. [PMID: 27635022 DOI: 10.1177/0003702816662600] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 01/04/2016] [Indexed: 06/06/2023]
Abstract
The key challenge of time-resolved Raman spectroscopy is the identification of the constituent species and the analysis of the kinetics of the underlying reaction network. In this work we present an integral approach that allows for determining both the component spectra and the rate constants simultaneously from a series of vibrational spectra. It is based on an algorithm for nonnegative matrix factorization that is applied to the experimental data set following a few pre-processing steps. As a prerequisite for physically unambiguous solutions, each component spectrum must include one vibrational band that does not significantly interfere with the vibrational bands of other species. The approach is applied to synthetic "experimental" spectra derived from model systems comprising a set of species with component spectra differing with respect to their degree of spectral interferences and signal-to-noise ratios. In each case, the species involved are connected via monomolecular reaction pathways. The potential and limitations of the approach for recovering the respective rate constants and component spectra are discussed.
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34
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Gkogkou D, Schreiber B, Shaykhutdinov T, Ly HK, Kuhlmann U, Gernert U, Facsko S, Hildebrandt P, Esser N, Hinrichs K, Weidinger IM, Oates TWH. Polarization- and Wavelength-Dependent Surface-Enhanced Raman Spectroscopy Using Optically Anisotropic Rippled Substrates for Sensing. ACS Sens 2016. [DOI: 10.1021/acssensors.5b00176] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dimitra Gkogkou
- Humboldt-Universität zu Berlin, School of Analytical Sciences
Adlershof (SALSA), IRIS-Building,
Unter den Linden 6, D-10099 Berlin, Germany
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., ISAS Berlin, Schwarzschildstr. 8, D-12489 Berlin, Germany
| | - Benjamin Schreiber
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf e.V., D-01314 Dresden, Germany
| | - Timur Shaykhutdinov
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., ISAS Berlin, Schwarzschildstr. 8, D-12489 Berlin, Germany
| | | | | | | | - Stefan Facsko
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf e.V., D-01314 Dresden, Germany
| | | | - Norbert Esser
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., ISAS Berlin, Schwarzschildstr. 8, D-12489 Berlin, Germany
| | - Karsten Hinrichs
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., ISAS Berlin, Schwarzschildstr. 8, D-12489 Berlin, Germany
| | | | - Thomas W. H. Oates
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., ISAS Berlin, Schwarzschildstr. 8, D-12489 Berlin, Germany
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35
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Kafentzi MC, Orio M, Réglier M, Yao S, Kuhlmann U, Hildebrandt P, Driess M, Simaan AJ, Ray K. Changing the chemical and physical properties of high valent heterobimetallic bis-(μ-oxido) Cu–Ni complexes by ligand effects. Dalton Trans 2016; 45:15994-16000. [DOI: 10.1039/c6dt02391f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [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
Two new heterobimetallic [LNiO2Cu(RPY2)]+ (RPY2 = N-substituted bis 2-pyridyl(ethylamine) ligands with R = indane, 3a or R = Me, 3b) complexes have been spectroscopically trapped at low temperatures.
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Affiliation(s)
| | - Maylis Orio
- Aix Marseille Univ
- CNRS
- Centrale Marseille
- iSm2
- Marseille
| | | | - Shenglai Yao
- Department of Chemistry
- Technische Universität Berlin
- 10623 Berlin
- Germany
| | - Uwe Kuhlmann
- Department of Chemistry
- Technische Universität Berlin
- 10623 Berlin
- Germany
| | - Peter Hildebrandt
- Department of Chemistry
- Technische Universität Berlin
- 10623 Berlin
- Germany
| | - Matthias Driess
- Department of Chemistry
- Technische Universität Berlin
- 10623 Berlin
- Germany
| | | | - Kallol Ray
- Department of Chemistry
- Humboldt-Universität zu Berlin
- 12489 Berlin
- Germany
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36
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Rauen T, Eitner F, Fitzner C, Sommerer C, Zeier M, Otte B, Panzer U, Peters H, Benck U, Mertens PR, Kuhlmann U, Witzke O, Gross O, Vielhauer V, Mann JFE, Hilgers RD, Floege J. Intensive Supportive Care plus Immunosuppression in IgA Nephropathy. N Engl J Med 2015; 373:2225-36. [PMID: 26630142 DOI: 10.1056/nejmoa1415463] [Citation(s) in RCA: 424] [Impact Index Per Article: 47.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
BACKGROUND The outcomes of immunosuppressive therapy, when added to supportive care, in patients with IgA nephropathy are uncertain. METHODS We conducted a multicenter, open-label, randomized, controlled trial with a two-group, parallel, group-sequential design. During a 6-month run-in phase, supportive care (in particular, blockade of the renin-angiotensin system) was adjusted on the basis of proteinuria. Patients who had persistent proteinuria with urinary protein excretion of at least 0.75 g per day were randomly assigned to receive supportive care alone (supportive-care group) or supportive care plus immunosuppressive therapy (immunosuppression group) for 3 years. The primary end points in hierarchical order were full clinical remission at the end of the trial (protein-to-creatinine ratio <0.2 [with both protein and creatinine measured in grams] and a decrease in the estimated glomerular filtration rate [eGFR] of <5 ml per minute per 1.73 m(2) of body-surface area from baseline) and a decrease in the eGFR of at least 15 ml per minute per 1.73 m(2) at the end of the trial. The primary end points were analyzed with the use of logistic-regression models. RESULTS The run-in phase was completed by 309 of 337 patients. The proteinuria level decreased to less than 0.75 g of urinary protein excretion per day in 94 patients. Of the remaining 162 patients who consented to undergo randomization, 80 were assigned to the supportive-care group, and 82 to the immunosuppression group. After 3 years, 4 patients (5%) in the supportive-care group, as compared with 14 (17%) in the immunosuppression group, had a full clinical remission (P=0.01). A total of 22 patients (28%) in the supportive-care group and 21 (26%) in the immunosuppression group had a decrease in the eGFR of at least 15 ml per minute per 1.73 m(2) (P=0.75). There was no significant difference in the annual decline in eGFR between the two groups. More patients in the immunosuppression group than in the supportive-care group had severe infections, impaired glucose tolerance, and weight gain of more than 5 kg in the first year of treatment. One patient in the immunosuppression group died of sepsis. CONCLUSIONS The addition of immunosuppressive therapy to intensive supportive care in patients with high-risk IgA nephropathy did not significantly improve the outcome, and during the 3-year study phase, more adverse effects were observed among the patients who received immunosuppressive therapy, with no change in the rate of decrease in the eGFR. (Funded by the German Federal Ministry of Education and Research; STOP-IgAN ClinicalTrials.gov number, NCT00554502.).
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Affiliation(s)
- Thomas Rauen
- From the Division of Nephrology and Clinical Immunology (T.R., F.E., J.F.) and Department of Medical Statistics (C.F., R.-D.H.), RWTH Aachen University, Aachen, Bayer Pharma, Kidney Diseases Research, Wuppertal (F.E.), Department of Nephrology, University of Heidelberg, Heidelberg (C.S., M.Z.), Internal Medicine D, Department of Nephrology, Hypertension and Rheumatology, University Hospital Muenster, Muenster (B.O.), University Medical Center Hamburg-Eppendorf, Hamburg (U.P.), Department of Nephrology and Dieter Scheffner Center for Medical Education, Charité Campus Mitte, Charité-Universitätsmedizin Berlin, Berlin (H.P.), Department of Medicine V, University Medical Center Mannheim, University of Heidelberg, Mannheim (U.B.), Department of Nephrology and Hypertension, Diabetes and Endocrinology, Otto-von-Guericke University, Magdeburg (P.R.M.), Medical Clinic III, Central Hospital Bremen, Bremen (U.K.), Department of Nephrology, University Hospital Essen, University of Duisburg-Essen, Essen (O.W.), Clinic for Nephrology and Rheumatology, University Medical Center Goettingen, Goettingen (O.G.), and Nephrologisches Zentrum, Medizinische Klinik und Poliklinik IV, Klinikum der Ludwig-Maximilians-Universität (V.V.), and Department of Nephrology, Hypertension and Rheumatology, Munich General Hospital (J.F.E.M.), Munich - all in Germany
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Bruun S, Stoeppler D, Keidel A, Kuhlmann U, Luck M, Diehl A, Geiger MA, Woodmansee D, Trauner D, Hegemann P, Oschkinat H, Hildebrandt P, Stehfest K. Light-Dark Adaptation of Channelrhodopsin Involves Photoconversion between the all-trans and 13-cis Retinal Isomers. Biochemistry 2015; 54:5389-400. [PMID: 26237332 DOI: 10.1021/acs.biochem.5b00597] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Channelrhodopsins (ChR) are light-gated ion channels of green algae that are widely used to probe the function of neuronal cells with light. Most ChRs show a substantial reduction in photocurrents during illumination, a process named "light adaptation". The main objective of this spectroscopic study was to elucidate the molecular processes associated with light-dark adaptation. Here we show by liquid and solid-state nuclear magnetic resonance spectroscopy that the retinal chromophore of fully dark-adapted ChR is exclusively in an all-trans configuration. Resonance Raman (RR) spectroscopy, however, revealed that already low light intensities establish a photostationary equilibrium between all-trans,15-anti and 13-cis,15-syn configurations at a ratio of 3:1. The underlying photoreactions involve simultaneous isomerization of the C(13)═C(14) and C(15)═N bonds. Both isomers of this DAapp state may run through photoinduced reaction cycles initiated by photoisomerization of only the C(13)═C(14) bond. RR spectroscopic experiments further demonstrated that photoinduced conversion of the apparent dark-adapted (DAapp) state to the photocycle intermediates P500 and P390 is distinctly more efficient for the all-trans isomer than for the 13-cis isomer, possibly because of different chromophore-water interactions. Our data demonstrating two complementary photocycles of the DAapp isomers are fully consistent with the existence of two conducting states that vary in quantitative relation during light-dark adaptation, as suggested previously by electrical measurements.
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Affiliation(s)
- Sara Bruun
- Technische Universität Berlin , Institut für Chemie, Sekr. PC14, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Daniel Stoeppler
- Leibniz-Institut für Molekulare Pharmakologie (FMP) , Robert-Rössle-Strasse 10, 13125 Berlin, Germany
| | - Anke Keidel
- Technische Universität Berlin , Institut für Chemie, Sekr. PC14, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Uwe Kuhlmann
- Technische Universität Berlin , Institut für Chemie, Sekr. PC14, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Meike Luck
- Humboldt-Universität zu Berlin , Institut für Biologie, Invalidenstrasse 42, D-10115 Berlin, Germany
| | - Anne Diehl
- Leibniz-Institut für Molekulare Pharmakologie (FMP) , Robert-Rössle-Strasse 10, 13125 Berlin, Germany
| | - Michel-Andreas Geiger
- Leibniz-Institut für Molekulare Pharmakologie (FMP) , Robert-Rössle-Strasse 10, 13125 Berlin, Germany
| | - David Woodmansee
- Department of Chemistry, Ludwig-Maximilians-Universität München , Butenandtstraße 5-13, 81377 München, Germany
| | - Dirk Trauner
- Department of Chemistry, Ludwig-Maximilians-Universität München , Butenandtstraße 5-13, 81377 München, Germany
| | - Peter Hegemann
- Humboldt-Universität zu Berlin , Institut für Biologie, Invalidenstrasse 42, D-10115 Berlin, Germany
| | - Hartmut Oschkinat
- Leibniz-Institut für Molekulare Pharmakologie (FMP) , Robert-Rössle-Strasse 10, 13125 Berlin, Germany
| | - Peter Hildebrandt
- Technische Universität Berlin , Institut für Chemie, Sekr. PC14, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Katja Stehfest
- Humboldt-Universität zu Berlin , Institut für Biologie, Invalidenstrasse 42, D-10115 Berlin, Germany
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Siebert E, Rippers Y, Frielingsdorf S, Fritsch J, Schmidt A, Kalms J, Katz S, Lenz O, Scheerer P, Paasche L, Pelmenschikov V, Kuhlmann U, Mroginski MA, Zebger I, Hildebrandt P. Resonance Raman Spectroscopic Analysis of the [NiFe] Active Site and the Proximal [4Fe-3S] Cluster of an O2-Tolerant Membrane-Bound Hydrogenase in the Crystalline State. J Phys Chem B 2015. [DOI: 10.1021/acs.jpcb.5b04119] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Elisabeth Siebert
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Yvonne Rippers
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Stefan Frielingsdorf
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Johannes Fritsch
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Andrea Schmidt
- Charité − Universitätsmedizin Berlin, Institut für Medizinische Physik und Biophysik (CC2), Group
Protein X-ray Crystallography and Signal Transduction, Charitéplatz 1, D-10117 Berlin, Germany
| | - Jacqueline Kalms
- Charité − Universitätsmedizin Berlin, Institut für Medizinische Physik und Biophysik (CC2), Group
Protein X-ray Crystallography and Signal Transduction, Charitéplatz 1, D-10117 Berlin, Germany
| | - Sagie Katz
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Oliver Lenz
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Patrick Scheerer
- Charité − Universitätsmedizin Berlin, Institut für Medizinische Physik und Biophysik (CC2), Group
Protein X-ray Crystallography and Signal Transduction, Charitéplatz 1, D-10117 Berlin, Germany
| | - Lars Paasche
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Vladimir Pelmenschikov
- Technische
Universität Berlin, Institut für Chemie, Sekr. C7, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Uwe Kuhlmann
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Maria Andrea Mroginski
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Ingo Zebger
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Peter Hildebrandt
- Technische
Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
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39
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Sezer M, Kielb P, Kuhlmann U, Mohrmann H, Schulz C, Heinrich D, Schlesinger R, Heberle J, Weidinger IM. Surface Enhanced Resonance Raman Spectroscopy Reveals Potential Induced Redox and Conformational Changes of Cytochrome c Oxidase on Electrodes. J Phys Chem B 2015; 119:9586-91. [PMID: 26135359 DOI: 10.1021/acs.jpcb.5b03206] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [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
Immobilization of Cytochrome c oxidase (CcO) on electrodes makes voltage-driven reduction of oxygen to water possible. Efficient catalytic turnover in CcO/electrode systems is, however, often observed at large overpotentials that cannot be rationalized by the redox properties of the enzyme itself. To understand the structural basis for this observation, CcO was electrostatically adsorbed on amino-functionalized Ag electrodes, and the redox transitions of heme a and a3 were monitored via surface enhanced resonance Raman spectroscopy (SERRS) as a function of applied potential. Under completely anaerobic conditions, the reduction of heme a3 could be seen at potentials close to those measured in solution indicating an intact catalytic center. However, in the immobilized state, a new non-native heme species was observed that exhibited a redox potential much more negative than measured for the native hemes. Analysis of the high and low frequency SERR spectra indicated that this new species is formed from heme a upon axial loss of one histidine ligand. It is concluded that the formation of the non-native heme a species alters the potential-dependent electron supply to the catalytic reaction and, thus, can have a impact on the applicability of this enzyme in biofuel cells.
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Affiliation(s)
- Murat Sezer
- †Institut für Chemie PC 14, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Patrycja Kielb
- †Institut für Chemie PC 14, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Uwe Kuhlmann
- †Institut für Chemie PC 14, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Hendrik Mohrmann
- ‡Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Claudia Schulz
- †Institut für Chemie PC 14, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
| | - Dorothea Heinrich
- ‡Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Ramona Schlesinger
- ‡Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Joachim Heberle
- ‡Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
| | - Inez M Weidinger
- †Institut für Chemie PC 14, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany
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Affiliation(s)
- J Weber
- Robert Bosch Hospital, Teaching Hospital, Eberhard Karls University of Tübingen, Department of Internal Medicine, Stuttgart, FRG
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Augustin R, Kuhlmann U, Schmid E, Wisser H. Bacterial peritonitis in CAPD: pathogenesis, symptoms, therapy and progress. Contrib Nephrol 2015; 57:10-22. [PMID: 3677682 DOI: 10.1159/000414259] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- R Augustin
- Robert-Bosch-Hospital, Division of Nephrology and Clinical Chemistry, Stuttgart, FRG
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Schmid E, Augustin R, Kuhlmann U, Machleidt C, Bartz V. Quantitative in vitro contamination and recovery studies: the flush principle in CAPD. Contrib Nephrol 2015; 57:185-90. [PMID: 3677692 DOI: 10.1159/000414281] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- E Schmid
- Department for Nephrology, Robert-Bosch-Hospital, Stuttgart, FRG
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Adamczack J, Hoffmann M, Papke U, Haufschildt K, Nicke T, Bröring M, Sezer M, Weimar R, Kuhlmann U, Hildebrandt P, Layer G. NirN protein from Pseudomonas aeruginosa is a novel electron-bifurcating dehydrogenase catalyzing the last step of heme d1 biosynthesis. J Biol Chem 2014; 289:30753-30762. [PMID: 25204657 DOI: 10.1074/jbc.m114.603886] [Citation(s) in RCA: 20] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Heme d1 plays an important role in denitrification as the essential cofactor of the cytochrome cd1 nitrite reductase NirS. At present, the biosynthesis of heme d1 is only partially understood. The last step of heme d1 biosynthesis requires a so far unknown enzyme that catalyzes the introduction of a double bond into one of the propionate side chains of the tetrapyrrole yielding the corresponding acrylate side chain. In this study, we show that a Pseudomonas aeruginosa PAO1 strain lacking the NirN protein does not produce heme d1. Instead, the NirS purified from this strain contains the heme d1 precursor dihydro-heme d1 lacking the acrylic double bond, as indicated by UV-visible absorption spectroscopy and resonance Raman spectroscopy. Furthermore, the dihydro-heme d1 was extracted from purified NirS and characterized by UV-visible absorption spectroscopy and finally identified by high-resolution electrospray ionization mass spectrometry. Moreover, we show that purified NirN from P. aeruginosa binds the dihydro-heme d1 and catalyzes the introduction of the acrylic double bond in vitro. Strikingly, NirN uses an electron bifurcation mechanism for the two-electron oxidation reaction, during which one electron ends up on its heme c cofactor and the second electron reduces the substrate/product from the ferric to the ferrous state. On the basis of our results, we propose novel roles for the proteins NirN and NirF during the biosynthesis of heme d1.
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Affiliation(s)
- Julia Adamczack
- Institute of Microbiology, Technische Universität Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany
| | - Martin Hoffmann
- Institute of Inorganic and Analytical Chemistry and Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
| | - Ulrich Papke
- Institute of Organic Chemistry, Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany; and
| | - Kristin Haufschildt
- Institute of Microbiology, Technische Universität Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany
| | - Tristan Nicke
- Institute of Microbiology, Technische Universität Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany
| | - Martin Bröring
- Institute of Inorganic and Analytical Chemistry and Technische Universität Braunschweig, Hagenring 30, 38106 Braunschweig, Germany
| | - Murat Sezer
- Institute of Chemistry, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Rebecca Weimar
- Institute of Chemistry, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Uwe Kuhlmann
- Institute of Chemistry, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Peter Hildebrandt
- Institute of Chemistry, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany
| | - Gunhild Layer
- Institute of Microbiology, Technische Universität Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany;.
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Li H, Guillemaud T, French BW, Kuhlmann U, Toepfer S. Phenotypic trait changes in laboratory--reared colonies of the maize herbivore, Diabrotica virgifera virgifera. Bull Entomol Res 2014; 104:97-115. [PMID: 24267312 DOI: 10.1017/s000748531300059x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The North American and European maize pest Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) was used to assess whether conditions of the natal field, subsequent laboratory rearing, or genetic population origin affect phenotypic traits of fitness, activity, or morphometrics. Standardized laboratory bioassays with large sample sizes revealed that none of the 16 tested traits, except crawling behaviours, appeared consistently stable across all seven tested colonies. Environmental conditions in the natal field of the F 0 generation affected trait averages of the subsequently reared F 1 generation in laboratory in ca. 47% of cases, and trait variability in 67% of cases. This was apparent for fitness and morphometrics, but less obvious for activity traits. Early generation laboratory rearing affected trait averages in ca. 56% of cases: morphometrics changed; fecundity and egg survival increased from F 1 to F 2. Trait variability increased or decreased in 38% of cases. Laboratory rearing for over more than 190 generations affected the trait averages in 60% of cases, reflected by decreases in flight activity and increases in body size, weight, and fecundity to some extent. It had little effect on trait variability, especially so for morphometric variability. The genetic population origin affected average levels of 55% and variability of 63% of phenotypic traits. A comparison among D. v. virgifera studies might be difficult if they use different populations or laboratory colonies. It is advised to consider possible effects of original field conditions, laboratory rearing, and population genetics when planning comparative studies targeting fitness, activity, or morphometric questions regarding Diabrotica species.
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Affiliation(s)
- H Li
- Chinese Ministry of Agriculture - CABI Joint Laboratory for Biosafety, Yuanmingyuan Western Road 2, CN - 100193 Beijing, People's Republic of China
| | - T Guillemaud
- INRA UMR, Route des Chappes 400, F - 06903 Sophia Antipolis, France
| | - B W French
- USDA ARS, North Central Agricultural Research Laboratory, Medary Avenue 2923, US - 57006 Brookings, South Dakota, USA
| | - U Kuhlmann
- CABI, Rue des Grillons 1, CH - 2800 Delémont, Switzerland
| | - S Toepfer
- CABI, Rue des Grillons 1, CH - 2800 Delémont, Switzerland
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Han XX, Chen L, Kuhlmann U, Schulz C, Weidinger IM, Hildebrandt P. Magnetic Titanium Dioxide Nanocomposites for Surface-Enhanced Resonance Raman Spectroscopic Determination and Degradation of Toxic Anilines and Phenols. Angew Chem Int Ed Engl 2014; 53:2481-4. [DOI: 10.1002/anie.201310123] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Indexed: 11/10/2022]
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Han XX, Chen L, Kuhlmann U, Schulz C, Weidinger IM, Hildebrandt P. Magnetische TiO2-Nanokomposite zur spektroskopischen Identifizierung und zum Abbau toxischer Aniline und Phenole. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201310123] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Han XX, Köhler C, Kozuch J, Kuhlmann U, Paasche L, Sivanesan A, Weidinger IM, Hildebrandt P. Potential-dependent surface-enhanced resonance Raman spectroscopy at nanostructured TiO2 : a case study on cytochrome b5. Small 2013; 9:4175-81. [PMID: 23861351 DOI: 10.1002/smll.201301070] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Revised: 05/03/2013] [Indexed: 05/22/2023]
Abstract
Nanostructured titanium dioxide (TiO2 ) electrodes, prepared by anodization of titanium, are employed to probe the electron-transfer process of cytochrome b5 (cyt b5 ) by surface-enhanced resonance Raman (SERR) spectroscopy. Concomitant with the increased nanoscopic surface roughness of TiO2 , achieved by raising the anodization voltage from 10 to 20 V, the enhancement factor increases from 2.4 to 8.6, which is rationalized by calculations of the electric field enhancement. Cyt b5 is immobilized on TiO2 under preservation of its native structure but it displays a non-ideal redox behavior due to the limited conductivity of the electrode material. The electron-transfer efficiency which depends on the crystalline phase of TiO2 has to be improved by appropriate doping for applications in bioelectrochemistry.
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Affiliation(s)
- Xiao Xia Han
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Strasse des 17. Juni 135, D-10623 Berlin, Germany
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López I, Ertem MZ, Maji S, Benet-Buchholz J, Keidel A, Kuhlmann U, Hildebrandt P, Cramer CJ, Batista VS, Llobet A. A Self-Improved Water-Oxidation Catalyst: Is One Site Really Enough? Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201307509] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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49
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López I, Ertem MZ, Maji S, Benet-Buchholz J, Keidel A, Kuhlmann U, Hildebrandt P, Cramer CJ, Batista VS, Llobet A. A Self-Improved Water-Oxidation Catalyst: Is One Site Really Enough? Angew Chem Int Ed Engl 2013; 53:205-9. [DOI: 10.1002/anie.201307509] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 10/25/2013] [Indexed: 12/20/2022]
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Abstract
Abstract
Chronic allograft nephropathy (CAN) and death with functioning graft due to cardiovascular disease (CVD) are the key determinants for long-term renal allograft survival. Chronic allograft nephropathy and cardiovascular disease are seen as manifestations of a single disease entity with a common pathogenesis including inflammation and accelerated atherogenesis. Therefore we investigated the relation between early post-transplant inflammatory burden and long-term graft survival.
In 64 consecutive renal transplant patients the acute phase reactants serum amyloid A (SAA) and serum C-reactive protein (S-CRP) as well as the macrophage product neopterin in urine (U-NEOP) and serum (S-NEOP) were determined daily during the immediate postoperative period (mean p.o.obs. χ = 29.2 ± 8.7 days, total of Σ = 1869 days). SAA and CRP were measured with high-sensitive assays (in mg/1; immune nephelometry, Dade Behring Co., Marburg, Germany), NEOP was measured with ELISA-technique (Brahms, Berlin, Germany) and related to serum and urine creatinine levels, resp. (in μπιοΐ/mol creatinine). The association between the mean values of these parameters and the survival distribution function of the 64 patients was tested using the log rank test and the Wilcoxon-test. In this analysis graft loss was defined as either resumption of dialysis treatment or patient death with functioning graft.
The 1- and 5- year graft survival rates in our patients were 93% and 76%, resp. The markers showed the following mean post-transplant levels: S-CRP χ = 21.3 ± 16.1 mg/1, SAA χ = 10.1 ± 6.5 mg/1, U-NEOP χ = 602 ± 427 mmol/mol creatinine and S-NEOP χ = 81 ± 60 μπιοΐ/mol creatinine. Both log rank test and Wilcoxon-test provided evidence that the graft survival is negatively related to the post-transplant levels of U-NEOP (p = 0.009 and ρ = 0.027, resp.). The markers S-NEOP (p = 0.074 and ρ = 0.116, resp.), SAA (p = 0.599 and ρ = 0.294, resp.), and S-CRP (p = 0.059 and ρ = 0.358, resp.) did not reach statistical significance. These findings support the impact of the inflammatory burden on graft survival. In particular, elevated post-transplant neopterin values, reflecting activated innate and adaptive responses, are predictive for long-term graft outcome.
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Affiliation(s)
- S. O. Grebe
- Clinic of Internal Medicine. Department of Nephrology, Philipps-University, Marburg, Germany
| | - U. Kuhlmann
- Clinic of Internal Medicine. Department of Nephrology, Philipps-University, Marburg, Germany
| | - T. F. Müller
- Brigham and Women's Hospital, PBB-170, Laboratory of Molecular Immunology, 75 Francis Street, Boston, MA 02115, Phone: ++1 617 732 5252, Fax: +1 617 264 6870
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