1
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Reinoso Schiller N, Bludau A, Mathes T, König A, von Landesberger T, Scheithauer S. Unpacking nudge sensu lato: insights from a scoping review. J Hosp Infect 2024; 143:168-177. [PMID: 37949370 DOI: 10.1016/j.jhin.2023.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 10/27/2023] [Accepted: 11/02/2023] [Indexed: 11/12/2023]
Abstract
Nudges may play an important role in improving infection prevention and control (IPC) in hospitals. However, despite the novelty of the framework, their objectives, strategies and implementation approaches are not new. This review aims to provide an overview of the methods typically used by nudge interventions in IPC in hospitals targeting healthcare workers (HCWs). The initial search in PubMed yielded nine hits. Consequently, the search criteria were broadened and a second search was conducted, introducing 'nudge sensu lato' which incorporates insights from sources beyond the traditional nudge framework while maintaining the same objectives, strategies and approaches. During the second search, PubMed, Epistemonikos, Web of Science and PsycInfo were searched in accordance with the PRISMA guidelines. Abstracts were screened, and reviewers from an interdisciplinary team read the full text of selected papers. In total, 5706 unique primary studies were identified. Of these, 67 were included in the review, and only four were listed as nudge sensu stricto, focusing on changing HCWs' hand hygiene. All articles reported positive intervention outcomes. Of the 56 articles focused on improving hand hygiene compliance, 71.4% had positive outcomes. For healthcare equipment disinfection, 50% of studies showed significant results. Guideline adherence interventions had a 66.7% significant outcome rate. The concept of nudge sensu lato was introduced, encompassing interventions that employ strategies, methods and implementation approaches found in the nudge framework. The findings demonstrate that this concept can enhance the scientific development of more impactful nudges. This may help clinicians, researchers and policy makers to develop and implement effective nudging interventions.
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Affiliation(s)
- N Reinoso Schiller
- Department for Infection Control and Infectious Diseases, University Medical Centre Göttingen, Georg-August University Göttingen, Göttingen, Germany.
| | - A Bludau
- Department for Infection Control and Infectious Diseases, University Medical Centre Göttingen, Georg-August University Göttingen, Göttingen, Germany
| | - T Mathes
- Department of Medical Statistics, University Medical Centre Göttingen, Georg-August University Göttingen, Göttingen, Germany
| | - A König
- Department of Gastroenterology and Gastrointestinal Oncology, University Medical Centre Göttingen, Georg-August University Göttingen, Göttingen, Germany
| | - T von Landesberger
- Chair for Visualization and Visual Analytics, University of Cologne, Cologne, Germany
| | - S Scheithauer
- Department for Infection Control and Infectious Diseases, University Medical Centre Göttingen, Georg-August University Göttingen, Göttingen, Germany
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2
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Hontani Y, Mehlhorn J, Domratcheva T, Beck S, Kloz M, Hegemann P, Mathes T, Kennis JTM. Spectroscopic and Computational Observation of Glutamine Tautomerization in the Blue Light Sensing Using Flavin Domain Photoreaction. J Am Chem Soc 2023; 145:1040-1052. [PMID: 36607126 PMCID: PMC9853863 DOI: 10.1021/jacs.2c10621] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Blue light sensing using flavin (BLUF) domains constitute a family of flavin-binding photoreceptors of bacteria and eukaryotic algae. BLUF photoactivation proceeds via a light-driven hydrogen-bond switch among flavin adenine dinucleotide (FAD) and glutamine and tyrosine side chains, whereby FAD undergoes electron and proton transfer with tyrosine and is subsequently re-oxidized by a hydrogen back-shuttle in picoseconds, constituting an important model system to understand proton-coupled electron transfer in biology. The specific structure of the hydrogen-bond patterns and the prevalence of glutamine tautomeric states in dark-adapted (DA) and light-activated (LA) states have remained controversial. Here, we present a combined femtosecond stimulated Raman spectroscopy (FSRS), computational chemistry, and site-selective isotope labeling Fourier-transform infrared spectroscopy (FTIR) study of the Slr1694 BLUF domain. FSRS showed distinct vibrational bands from the FADS1 singlet excited state. We observed small but significant shifts in the excited-state vibrational frequency patterns of the DA and LA states, indicating that these frequencies constitute a sensitive probe for the hydrogen-bond arrangement around FAD. Excited-state model calculations utilizing four different realizations of hydrogen bond patterns and glutamine tautomeric states were consistent with a BLUF reaction model that involved glutamine tautomerization to imidic acid, accompanied by a rotation of its side chain. A combined FTIR and double-isotope labeling study, with 13C labeling of FAD and 15N labeling of glutamine, identified the glutamine imidic acid C═N stretch vibration in the LA state and the Gln C═O in the DA state. Hence, our study provides support for glutamine tautomerization and side-chain rotation in the BLUF photoreaction.
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Affiliation(s)
- Yusaku Hontani
- Department
of Physics and Astronomy, Vrije Universiteit
Amsterdam, 1081 HV Amsterdam, De Boelelaan, The Netherlands
| | - Jennifer Mehlhorn
- Institut
für Biologie, Experimentelle Biophysik, Humboldt Universität zu Berlin, Invalidenstrasse 42, D-10115 Berlin, Germany
| | - Tatiana Domratcheva
- Department
of Biomolecular Mechanisms, Max Planck Institute
for Medical Research, 69120 Heidelberg, Germany,Department
of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Sebastian Beck
- Department
of Chemistry, Humboldt-Universität
zu Berlin, Brook-Taylor-Str.
2, 12489 Berlin, Germany
| | - Miroslav Kloz
- Department
of Physics and Astronomy, Vrije Universiteit
Amsterdam, 1081 HV Amsterdam, De Boelelaan, The Netherlands,Institute
of Physics, ELI-Beamlines, Na Slovance 2, 182
21 Praha 8, Czech Republic
| | - Peter Hegemann
- Institut
für Biologie, Experimentelle Biophysik, Humboldt Universität zu Berlin, Invalidenstrasse 42, D-10115 Berlin, Germany
| | - Tilo Mathes
- Department
of Physics and Astronomy, Vrije Universiteit
Amsterdam, 1081 HV Amsterdam, De Boelelaan, The Netherlands,Institut
für Biologie, Experimentelle Biophysik, Humboldt Universität zu Berlin, Invalidenstrasse 42, D-10115 Berlin, Germany
| | - John T. M. Kennis
- Department
of Physics and Astronomy, Vrije Universiteit
Amsterdam, 1081 HV Amsterdam, De Boelelaan, The Netherlands,
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3
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Rombey T, Goossen K, Kugler C, De Santis KK, Breuing J, Mathes T, Hess S, Burchard R, Pieper D. Hospital volume-outcome relationship in total knee arthroplasty: a systematic review and dose-response meta-analysis. Das Gesundheitswesen 2021. [DOI: 10.1055/s-0041-1732748] [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: 10/20/2022]
Affiliation(s)
- T Rombey
- Institut für Forschung in der Operativen Medizin, Universität Witten/Herdecke
| | - K Goossen
- Institut für Forschung in der Operativen Medizin, Universität Witten/Herdecke
| | - C Kugler
- Institut für Forschung in der Operativen Medizin, Universität Witten/Herdecke
| | - KK De Santis
- Institut für Forschung in der Operativen Medizin, Universität Witten/Herdecke
- Leibniz Institut für Präventiosforschung und Epidemiologie (BIPS)
| | - J Breuing
- Institut für Forschung in der Operativen Medizin, Universität Witten/Herdecke
| | - T Mathes
- Institut für Forschung in der Operativen Medizin, Universität Witten/Herdecke
| | - S Hess
- Institut für Forschung in der Operativen Medizin, Universität Witten/Herdecke
| | - R Burchard
- Klinik für Orthopädie und Unfallchirurgie, Lahn-Dill-Kliniken Dillenburg
- Fakultät für Gesundheit, Universität Witten/Herdecke
- Zentrum für Orthopädie und Unfallchirurgie, Universität Gießen und Marburg
| | - D Pieper
- Institut für Forschung in der Operativen Medizin, Universität Witten/Herdecke
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4
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Caruso R, Mathes T, Martens EC, Kamada N, Nusrat A, Inohara N, Núñez G. A specific gene-microbe interaction drives the development of Crohn's disease-like colitis in mice. Sci Immunol 2020; 4:4/34/eaaw4341. [PMID: 31004013 DOI: 10.1126/sciimmunol.aaw4341] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 03/07/2019] [Indexed: 12/12/2022]
Abstract
Bacterial dysbiosis is associated with Crohn's disease (CD), a chronic intestinal inflammatory disorder thought to result from an abnormal immune response against intestinal bacteria in genetically susceptible individuals. However, it is unclear whether dysbiosis is a cause or consequence of intestinal inflammation and whether overall dysbiosis or specific bacteria trigger the disease. Here, we show that the combined deficiency of NOD2 and phagocyte NADPH oxidase, two CD susceptibility genes, triggers early-onset spontaneous TH1-type intestinal inflammation in mice with the pathological hallmarks of CD. Disease was induced by Mucispirillum schaedleri, a Gram-negative mucus-dwelling anaerobe. NOD2 and CYBB deficiencies led to marked accumulation of Mucispirillum, which was associated with impaired neutrophil recruitment and killing of the bacterium by luminal neutrophils. Maternal immunoglobulins against Mucispirillum protected mutant mice from disease during breastfeeding. Our results indicate that a specific intestinal microbe triggers CD-like disease in the presence of impaired clearance of the bacterium by innate immunity.
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Affiliation(s)
- R Caruso
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.,Rogel Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - T Mathes
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.,Rogel Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - E C Martens
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - N Kamada
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - A Nusrat
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - N Inohara
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - G Núñez
- Department of Pathology, University of Michigan Medical School, Ann Arbor, MI 48109, USA. .,Rogel Cancer Center, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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5
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Zayner JP, Mathes T, Sosnick TR, Kennis JTM. Helical Contributions Mediate Light-Activated Conformational Change in the LOV2 Domain of Avena sativa Phototropin 1. ACS Omega 2019; 4:1238-1243. [PMID: 31459397 PMCID: PMC6648828 DOI: 10.1021/acsomega.8b02872] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 01/02/2019] [Indexed: 06/10/2023]
Abstract
Algae, plants, bacteria, and fungi contain flavin-binding light-oxygen-voltage (LOV) domains that function as blue light sensors to control cellular responses to light. In the second LOV domain of phototropins, called LOV2 domains, blue light illumination leads to covalent bond formation between protein and flavin that induces the dissociation and unfolding of a C-terminally attached α helix (Jα) and the N-terminal helix (A'α). To date, the majority of studies on these domains have focused on versions that contain truncations in the termini, which creates difficulties when extrapolating to the much larger proteins that contain these domains. Here, we study the influence of deletions and extensions of the A'α helix of the LOV2 domain of Avena sativa phototropin 1 (AsLOV2) on the light-triggered structural response of the protein by Fourier-transform infrared difference spectroscopy. Deletion of the A'α helix abolishes the light-induced unfolding of Jα, whereas extensions of the A'α helix lead to an attenuated structural change of Jα. These results are different from shorter constructs, indicating that the conformational changes in full-length phototropin LOV domains might not be as large as previously assumed, and that the well-characterized full unfolding of the Jα helix in AsLOV2 with short A'α helices may be considered a truncation artifact. It also suggests that the N- and C-terminal helices of phot-LOV2 domains are necessary for allosteric regulation of the phototropin kinase domain and may provide a basis for signal integration of LOV1 and LOV2 domains in phototropins.
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Affiliation(s)
- Josiah P. Zayner
- Department of Biochemistry
and Molecular Biology, The University of
Chicago, Chicago 60637, United States
| | - Tilo Mathes
- Biophysics
Section, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Tobin R. Sosnick
- Department of Biochemistry
and Molecular Biology, The University of
Chicago, Chicago 60637, United States
- Institute
for Biophysical Dynamics, The University
of Chicago, Chicago, Illinois 60637 United States
| | - John T. M. Kennis
- Biophysics
Section, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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6
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Sommer C, Dietz MS, Patschkowski T, Mathes T, Kottke T. Light-Induced Conformational Changes in the Plant Cryptochrome Photolyase Homology Region Resolved by Selective Isotope Labeling and Infrared Spectroscopy. Photochem Photobiol 2017; 93:881-887. [DOI: 10.1111/php.12750] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 02/10/2017] [Indexed: 11/28/2022]
Affiliation(s)
- Constanze Sommer
- Physical and Biophysical Chemistry; Department of Chemistry; Bielefeld University; Bielefeld Germany
| | - Marina S. Dietz
- Physical and Biophysical Chemistry; Department of Chemistry; Bielefeld University; Bielefeld Germany
| | - Thomas Patschkowski
- Proteome and Metabolome Research (Bio 27); Department of Biology; Bielefeld University; Bielefeld Germany
| | - Tilo Mathes
- Department of Biology; Experimental Biophysics; Humboldt-Universität zu Berlin; Berlin Germany
| | - Tilman Kottke
- Physical and Biophysical Chemistry; Department of Chemistry; Bielefeld University; Bielefeld Germany
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7
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Zhu J, Mathes T, Hontani Y, Alexandre MTA, Toh KC, Hegemann P, Kennis JTM. Photoadduct Formation from the FMN Singlet Excited State in the LOV2 Domain of Chlamydomonas reinhardtii Phototropin. J Phys Chem Lett 2016; 7:4380-4384. [PMID: 27766868 DOI: 10.1021/acs.jpclett.6b02075] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The two light, oxygen, and voltage domains of phototropin are blue-light photoreceptor domains that control various functions in plants and green algae. The key step of the light-driven reaction is the formation of a photoadduct between its FMN chromophore and a conserved cysteine, where the canonical reaction proceeds through the FMN triplet state. Here, complete photoreaction mapping of CrLOV2 from Chlamydomonas reinhardtii phototropin and AsLOV2 from Avena sativa phototropin-1 was realized by ultrafast broadband spectroscopy from femtoseconds to microseconds. We demonstrate that in CrLOV2, a direct photoadduct formation channel originates from the initially excited singlet state, in addition to the canonical reaction through the triplet state. This direct photoadduct reaction is coupled by a proton or hydrogen transfer process, as indicated by a significant kinetic isotope effect of 1.4 on the fluorescence lifetime. Kinetic model analyses showed that 38% of the photoadducts are generated from the singlet excited state.
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Affiliation(s)
- Jingyi Zhu
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit , 1081 De Boelelaan, 1081 HV Amsterdam, The Netherlands
| | - Tilo Mathes
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit , 1081 De Boelelaan, 1081 HV Amsterdam, The Netherlands
| | - Yusaku Hontani
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit , 1081 De Boelelaan, 1081 HV Amsterdam, The Netherlands
| | - Maxime T A Alexandre
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit , 1081 De Boelelaan, 1081 HV Amsterdam, The Netherlands
| | - K C Toh
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit , 1081 De Boelelaan, 1081 HV Amsterdam, The Netherlands
| | - Peter Hegemann
- Department of Biology, Experimental Biophysics, Humboldt-Universität zu Berlin , Invalidenstraße 42, 10115 Berlin, Germany
| | - John T M Kennis
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit , 1081 De Boelelaan, 1081 HV Amsterdam, The Netherlands
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8
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Konold PE, Mathes T, Weiβenborn J, Groot ML, Hegemann P, Kennis JTM. Unfolding of the C-Terminal Jα Helix in the LOV2 Photoreceptor Domain Observed by Time-Resolved Vibrational Spectroscopy. J Phys Chem Lett 2016; 7:3472-6. [PMID: 27537211 DOI: 10.1021/acs.jpclett.6b01484] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Light-triggered reactions of biological photoreceptors have gained immense attention for their role as molecular switches in their native organisms and for optogenetic application. The light, oxygen, and voltage 2 (LOV2) sensing domain of plant phototropin binds a C-terminal Jα helix that is docked on a β-sheet and unfolds upon light absorption by the flavin mononucleotide (FMN) chromophore. In this work, the signal transduction pathway of LOV2 from Avena sativa was investigated using time-resolved infrared spectroscopy from picoseconds to microseconds. In D2O buffer, FMN singlet-to-triplet conversion occurs in 2 ns and formation of the covalent cysteinyl-FMN adduct in 10 μs. We observe a two-step unfolding of the Jα helix: The first phase occurs concomitantly with Cys-FMN covalent adduct formation in 10 μs, along with hydrogen-bond rupture of the FMN C4═O with Gln-513, motion of the β-sheet, and an additional helical element. The second phase occurs in approximately 240 μs. The final spectrum at 500 μs is essentially identical to the steady-state light-minus-dark Fourier transform infrared spectrum, indicating that Jα helix unfolding is complete on that time scale.
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Affiliation(s)
- Patrick E Konold
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit , 1081 De Boelelaan, 1081HV Amsterdam, The Netherlands
| | - Tilo Mathes
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit , 1081 De Boelelaan, 1081HV Amsterdam, The Netherlands
| | - Jörn Weiβenborn
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit , 1081 De Boelelaan, 1081HV Amsterdam, The Netherlands
| | - Marie Louise Groot
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit , 1081 De Boelelaan, 1081HV Amsterdam, The Netherlands
| | - Peter Hegemann
- Department of Biology, Experimental Biophysics, Humboldt-Universität zu Berlin , Invalidenstraße 42, 10115 Berlin, Germany
| | - John T M Kennis
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit , 1081 De Boelelaan, 1081HV Amsterdam, The Netherlands
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9
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Affiliation(s)
- Tilo Mathes
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam Amsterdam, Netherlands
| | - John T M Kennis
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam Amsterdam, Netherlands
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10
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Mehlhorn J, Lindtner T, Richter F, Glass K, Steinocher H, Beck S, Hegemann P, Kennis JTM, Mathes T. Light-Induced Rearrangement of the β5 Strand in the BLUF Photoreceptor SyPixD (Slr1694). J Phys Chem Lett 2015; 6:4749-4753. [PMID: 26631358 DOI: 10.1021/acs.jpclett.5b02245] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The structural changes that facilitate signal transduction in blue light sensors using FAD (BLUF) photoreceptors and confer the stability of the rearranged hydrogen bond network between flavin and protein in the signaling state are still poorly understood. Here, we investigate a semiconserved Trp residue in SyPixD (Slr1694) by isotope-edited vibrational spectroscopy and site-directed mutagenesis. In the signaling state, a β-sheet structure involving the backbone of W91 is formed without apparent change of environment of the W91 indole side chain. Mutation of W91, however, significantly influences the stability of the light-adapted state, suggesting that backbone rigidity rather than discrete side-chain conformations govern the stability of the light-adapted state. On the basis of computational and crystallographic models, we interpret these changes as a +1 register shift of the β2/β5 interaction with an unaffected indole side-chain conformation, rather than a +2 register shift accompanied by an indole side-chain flip that was previously proposed on the basis of X-ray structures.
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Affiliation(s)
- Jennifer Mehlhorn
- Department of Biology, Experimental Biophysics, Humboldt-Universität zu Berlin , Invalidenstraße 42, 10115 Berlin, Germany
| | - Tom Lindtner
- Department of Biology, Experimental Biophysics, Humboldt-Universität zu Berlin , Invalidenstraße 42, 10115 Berlin, Germany
| | - Florian Richter
- Department of Biology, Experimental Biophysics, Humboldt-Universität zu Berlin , Invalidenstraße 42, 10115 Berlin, Germany
| | - Kathrin Glass
- Department of Biology, Experimental Biophysics, Humboldt-Universität zu Berlin , Invalidenstraße 42, 10115 Berlin, Germany
| | - Helena Steinocher
- Department of Biology, Experimental Biophysics, Humboldt-Universität zu Berlin , Invalidenstraße 42, 10115 Berlin, Germany
| | - Sebastian Beck
- Department of Chemistry, Humboldt-Universität zu Berlin , Brook-Taylor-Str. 2, 12489 Berlin, Germany
| | - Peter Hegemann
- Department of Biology, Experimental Biophysics, Humboldt-Universität zu Berlin , Invalidenstraße 42, 10115 Berlin, Germany
| | - John T M Kennis
- Department of Physics and Astronomy, Biophysics Section, Faculty of Sciences, Vrije Universiteit , De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Tilo Mathes
- Department of Biology, Experimental Biophysics, Humboldt-Universität zu Berlin , Invalidenstraße 42, 10115 Berlin, Germany
- Department of Physics and Astronomy, Biophysics Section, Faculty of Sciences, Vrije Universiteit , De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
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11
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Abstract
The resting and signaling structures of the blue-light sensing using flavin (BLUF) photoreceptor domains are still controversially debated due to differences in the molecular models obtained by crystal and NMR structures. Photocycles for the given preferred structural framework have been established, but a unifying picture combining experiment and theory remains elusive. We summarize present work on the AppA BLUF domain from both experiment and theory. We focus on IR and UV/vis spectra, and to what extent theory was able to reproduce experimental data and predict the structural changes upon formation of the signaling state. We find that the experimental observables can be theoretically reproduced employing any structural model, as long as the orientation of the signaling essential Gln63 and its tautomer state are a choice of the modeler. We also observe that few approaches are comparative, e.g., by considering all structures in the same context. Based on recent experimental findings and a few basic calculations, we suggest the possibility for a BLUF activation mechanism that only relies on electron transfer and its effect on the local electrostatics, not requiring an associated proton transfer. In this regard, we investigate the impact of dispersion correction on the interaction energies arising from weakly bound amino acids.
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Affiliation(s)
- Tilo Mathes
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, Netherlands ; Institut für Biologie/Experimentelle Biophysik, Humboldt Universität zu Berlin Berlin, Germany
| | - Jan P Götze
- School of Chemistry, University of St Andrews St Andrews, UK
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12
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Richter F, Scheib US, Mehlhorn J, Schubert R, Wietek J, Gernetzki O, Hegemann P, Mathes T, Möglich A. Upgrading a microplate reader for photobiology and all-optical experiments. Photochem Photobiol Sci 2015; 14:270-9. [PMID: 25373866 DOI: 10.1039/c4pp00361f] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Automation can vastly reduce the cost of experimental labor and thus facilitate high experimental throughput, but little off-the-shelf hardware for the automation of illumination experiments is commercially available. Here, we use inexpensive open-source electronics to add programmable illumination capabilities to a multimode microplate reader. We deploy this setup to characterize light-triggered phenomena in three different sensory photoreceptors. First, we study the photoactivation of Arabidopsis thaliana phytochrome B by light of different wavelengths. Second, we investigate the dark-state recovery kinetics of the Synechocystis sp. blue-light sensor Slr1694 at multiple temperatures and imidazole concentrations; while the kinetics of the W91F mutant of Slr1694 are strongly accelerated by imidazole, the wild-type protein is hardly affected. Third, we determine the light response of the Beggiatoa sp. photoactivatable adenylate cyclase bPAC in Chinese hamster ovary cells. bPAC is activated by blue light in dose-dependent manner with a half-maximal intensity of 0.58 mW cm(-2); intracellular cAMP spikes generated upon bPAC activation decay with a half time of about 5 minutes after light switch-off. Taken together, we present a setup which is easily assembled and which thus offers a facile approach to conducting illumination experiments at high throughput, reproducibility and fidelity.
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Affiliation(s)
- Florian Richter
- Humboldt-Universität zu Berlin, Institut für Biologie, Biophysikalische Chemie, Berlin, Germany.
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13
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Heilmann M, Christie JM, Kennis JTM, Jenkins GI, Mathes T. Photoinduced transformation of UVR8 monitored by vibrational and fluorescence spectroscopy. Photochem Photobiol Sci 2015; 14:252-7. [PMID: 25274012 DOI: 10.1039/c4pp00246f] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Tryptophan residues at the dimer interface of the plant photoreceptor UVR8 promote monomerisation after UV-B absorption via a so far unknown mechanism. Using FTIR spectroscopy we assign light-induced structural transitions of UVR8 mainly to amino acid side chains without major transformations of the secondary structure of the physiologically relevant C-terminal extension. Additionally, we assign the monomerisation associated increase and red shift of the UVR8 tryptophan emission to a photoinduced rearrangement of tryptophan side chains and a relocation of the aspartic acid residues D96 and D107, respectively. By illumination dependent emission spectroscopy we furthermore determined the quantum yield of photoinduced monomerisation to 20 ± 8%.
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Affiliation(s)
- Monika Heilmann
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, Bower Building, University of Glasgow, Glasgow G12 8QQ, UK
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14
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Mathes T, Heilmann M, Pandit A, Zhu J, Ravensbergen J, Kloz M, Fu Y, Smith BO, Christie JM, Jenkins GI, Kennis JTM. Proton-Coupled Electron Transfer Constitutes the Photoactivation Mechanism of the Plant Photoreceptor UVR8. J Am Chem Soc 2015; 137:8113-20. [DOI: 10.1021/jacs.5b01177] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Tilo Mathes
- Biophysics
Section, Department of Physics and Astronomy, Faculty of Sciences, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Monika Heilmann
- Institute
of Molecular, Cell and Systems Biology, College of Medical, Veterinary
and Life Sciences, Bower Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Anjali Pandit
- Biophysics
Section, Department of Physics and Astronomy, Faculty of Sciences, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
- Department
of Solid-State NMR, Leiden Institute of Chemistry, Leiden University, Einsteinweg
55, 2333 CC Leiden, The Netherlands
| | - Jingyi Zhu
- Biophysics
Section, Department of Physics and Astronomy, Faculty of Sciences, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Janneke Ravensbergen
- Biophysics
Section, Department of Physics and Astronomy, Faculty of Sciences, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Miroslav Kloz
- Biophysics
Section, Department of Physics and Astronomy, Faculty of Sciences, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Yinan Fu
- Institute
of Molecular, Cell and Systems Biology, College of Medical, Veterinary
and Life Sciences, Bower Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Brian O. Smith
- Institute
of Molecular, Cell and Systems Biology, College of Medical, Veterinary
and Life Sciences, Bower Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - John M. Christie
- Institute
of Molecular, Cell and Systems Biology, College of Medical, Veterinary
and Life Sciences, Bower Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Gareth I. Jenkins
- Institute
of Molecular, Cell and Systems Biology, College of Medical, Veterinary
and Life Sciences, Bower Building, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - John T. M. Kennis
- Biophysics
Section, Department of Physics and Astronomy, Faculty of Sciences, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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15
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Fudim R, Mehlhorn J, Berthold T, Weber S, Schleicher E, Kennis JTM, Mathes T. Photoinduced formation of flavin radicals in BLUF domains lacking the central glutamine. FEBS J 2015; 282:3161-74. [DOI: 10.1111/febs.13297] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 04/08/2015] [Accepted: 04/13/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Roman Fudim
- Institut für Biologie/Experimentelle Biophysik; Humboldt Universität zu Berlin; Berlin Germany
| | - Jennifer Mehlhorn
- Institut für Biologie/Experimentelle Biophysik; Humboldt Universität zu Berlin; Berlin Germany
| | - Thomas Berthold
- Institut für Physikalische Chemie; Albert-Ludwigs-Universität Freiburg; Freiburg Germany
| | - Stefan Weber
- Institut für Physikalische Chemie; Albert-Ludwigs-Universität Freiburg; Freiburg Germany
- Freiburg Institute for Advanced Studies (FRIAS); Albert-Ludwigs-Universität Freiburg; Germany
| | - Erik Schleicher
- Institut für Physikalische Chemie; Albert-Ludwigs-Universität Freiburg; Freiburg Germany
- Inorganic Chemistry Laboratory; University of Oxford; UK
| | - John T. M. Kennis
- Biophysics Section; Department of Physics and Astronomy; Faculty of Sciences; VU University; Amsterdam The Netherlands
| | - Tilo Mathes
- Institut für Biologie/Experimentelle Biophysik; Humboldt Universität zu Berlin; Berlin Germany
- Biophysics Section; Department of Physics and Astronomy; Faculty of Sciences; VU University; Amsterdam The Netherlands
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16
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Mathes T, Ravensbergen J, Kloz M, Gleichmann T, Gallagher KD, Woitowich NC, St Peter R, Kovaleva SE, Stojković EA, Kennis JTM. Femto- to Microsecond Photodynamics of an Unusual Bacteriophytochrome. J Phys Chem Lett 2015; 6:239-43. [PMID: 26263456 DOI: 10.1021/jz502408n] [Citation(s) in RCA: 33] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
A bacteriophytochrome from Stigmatella aurantiaca is an unusual member of the bacteriophytochrome family that is devoid of hydrogen bonding to the carbonyl group of ring D of the biliverdin (BV) chromophore. The photodynamics of BV in SaBphP1 wild type and the single mutant T289H reintroducing hydrogen bonding to ring D show that the strength of this particular weak interaction determines excited-state lifetime, Lumi-R quantum yield, and spectral heterogeneity. In particular, excited-state decay is faster in the absence of hydrogen-bonding to ring D, with excited-state half-lives of 30 and 80 ps for wild type and the T289H mutant, respectively. Concomitantly, the Lumi-R quantum yield is two times higher in wild type as compared with the T289H mutant. Furthermore, the spectral heterogeneity in the wild type is significantly higher than that in the T289H mutant. By extending the observable time domain to 25 μs, we observe a new deactivation pathway from the Lumi-R intermediate in the 100 ns time domain that corresponds to a backflip of ring D to the original Pr 15Za isomeric state.
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Affiliation(s)
- Tilo Mathes
- †Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Janneke Ravensbergen
- †Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Miroslav Kloz
- †Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Tobias Gleichmann
- †Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Kevin D Gallagher
- ‡Department of Biology, Northeastern Illinois University, 5500 North St. Louis Avenue, Chicago, Illinois 60625, United States
| | - Nicole C Woitowich
- ‡Department of Biology, Northeastern Illinois University, 5500 North St. Louis Avenue, Chicago, Illinois 60625, United States
| | - Rachael St Peter
- ‡Department of Biology, Northeastern Illinois University, 5500 North St. Louis Avenue, Chicago, Illinois 60625, United States
| | - Svetlana E Kovaleva
- ‡Department of Biology, Northeastern Illinois University, 5500 North St. Louis Avenue, Chicago, Illinois 60625, United States
| | - Emina A Stojković
- ‡Department of Biology, Northeastern Illinois University, 5500 North St. Louis Avenue, Chicago, Illinois 60625, United States
| | - John T M Kennis
- †Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
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17
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Wijaya IMM, Iwata T, Yamamoto J, Hitomi K, Iwai S, Getzoff ED, Kennis JTM, Mathes T, Kandori H. Flavin adenine dinucleotide chromophore charge controls the conformation of cyclobutane pyrimidine dimer photolyase α-helices. Biochemistry 2014; 53:5864-75. [PMID: 25152314 DOI: 10.1021/bi500638b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Observations of light-receptive enzyme complexes are usually complicated by simultaneous overlapping signals from the chromophore, apoprotein, and substrate, so that only the initial, ultrafast, photon-chromophore reaction and the final, slow, protein conformational change provide separate, nonoverlapping signals. Each provides its own advantages, whereas sometimes the overlapping signals from the intervening time scales still cannot be fully deconvoluted. We overcome the problem by using a novel method to selectively isotope-label the apoprotein but not the flavin adenine dinucleotide (FAD) cofactor. This allowed the Fourier transform infrared (FTIR) signals to be separated from the apoprotein, FAD cofactor, and DNA substrate. Consequently, a comprehensive structure-function study by FTIR spectroscopy of the Escherichia coli cyclobutane pyrimidine dimer photolyase (CPD-PHR) DNA repair enzyme was possible. FTIR signals could be identified and assigned upon FAD photoactivation and DNA repair, which revealed protein dynamics for both processes beyond simple one-electron reduction and ejection, respectively. The FTIR data suggest that the synergistic cofactor-protein partnership in CPD-PHR linked to changes in the shape of FAD upon one-electron reduction may be coordinated with conformational changes in the apoprotein, allowing it to fit the DNA substrate. Activation of the CPD-PHR chromophore primes the apoprotein for subsequent DNA repair, suggesting that CPD-PHR is not simply an electron-ejecting structure. When FAD is activated, changes in its structure may trigger coordinated conformational changes in the apoprotein and thymine carbonyl of the substrate, highlighting the role of Glu275. In contrast, during DNA repair and release processes, primary conformational changes occur in the enzyme and DNA substrate, with little contribution from the FAD cofactor and surrounding amino acid residues.
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Affiliation(s)
- I M Mahaputra Wijaya
- Department of Frontier Materials and ‡OptoBio Technology Research Center, Nagoya Institute of Technology , Showa-ku, Nagoya 466-8555, Japan
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18
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Stierl M, Penzkofer A, Kennis JTM, Hegemann P, Mathes T. Key Residues for the Light Regulation of the Blue Light-Activated Adenylyl Cyclase from Beggiatoa sp. Biochemistry 2014; 53:5121-30. [DOI: 10.1021/bi500479v] [Citation(s) in RCA: 29] [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: 11/28/2022]
Affiliation(s)
- Manuela Stierl
- Institut
für Biologie/Experimentelle Biophysik, Humboldt Universität zu Berlin, Invalidenstrasse 42, D-10115 Berlin, Germany
| | - Alfons Penzkofer
- Fakultät
für Physik, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
| | - John T. M. Kennis
- Department
of Exact Sciences/Biophysics, Vrije Universiteit, De Boelelaan 1081A, 1081 HV Amsterdam, The Netherlands
| | - Peter Hegemann
- Institut
für Biologie/Experimentelle Biophysik, Humboldt Universität zu Berlin, Invalidenstrasse 42, D-10115 Berlin, Germany
| | - Tilo Mathes
- Institut
für Biologie/Experimentelle Biophysik, Humboldt Universität zu Berlin, Invalidenstrasse 42, D-10115 Berlin, Germany
- Department
of Exact Sciences/Biophysics, Vrije Universiteit, De Boelelaan 1081A, 1081 HV Amsterdam, The Netherlands
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Abstract
Most biological photoreceptors are protein/cofactor complexes that induce a physiological reaction upon absorption of a photon. Therefore, these proteins represent signal converters that translate light into biological information. Researchers use this property to stimulate and study various biochemical processes conveniently and non-invasively by the application of light, an approach known as optogenetics. Here, we summarize the recent experimental progress on the family of blue light receptors using FAD (BLUF) receptors. Several BLUF photoreceptors modulate second messenger levels and thus represent highly interesting tools for optogenetic application. In order to activate a coupled effector protein, the flavin-binding pocket of the BLUF domain undergoes a subtle rearrangement of the hydrogen network upon blue light absorption. The hydrogen bond switch is facilitated by the ultrafast light-induced proton-coupled electron transfer (PCET) between a tyrosine and the flavin in less than a nanosecond and remains stable on a long enough timescale for biochemical reactions to take place. The cyclic nature of the photoinduced reaction makes BLUF domains powerful model systems to study protein/cofactor interaction, protein-modulated PCET and novel mechanisms of biological signalling. The ultrafast nature of the photoconversion as well as the subtle structural rearrangement requires sophisticated spectroscopic and molecular biological methods to study and understand this highly intriguing signalling process.
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Affiliation(s)
- John T M Kennis
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences , Vrije Universiteit , De Boelelaan 1081, 1081 HV Amsterdam , The Netherlands
| | - Tilo Mathes
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences , Vrije Universiteit , De Boelelaan 1081, 1081 HV Amsterdam , The Netherlands
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20
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Mathes T, Pieper D, Antoine SL, Eikermann M. Response to letter ‘Poor citation, coding and reporting: a review of adherence-enhancing interventions for highly active antiretroviral therapy creates an inaccurate picture of the state of the field’. HIV Med 2014; 15:383-4. [DOI: 10.1111/hiv.12138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- T Mathes
- Institute for Research in Operative Medicine, Faculty of Health, School of Medicine; Witten/Herdecke University; Cologne Germany
| | - D Pieper
- Institute for Research in Operative Medicine, Faculty of Health, School of Medicine; Witten/Herdecke University; Cologne Germany
| | - S-L Antoine
- Institute for Research in Operative Medicine, Faculty of Health, School of Medicine; Witten/Herdecke University; Cologne Germany
| | - M Eikermann
- Institute for Research in Operative Medicine, Faculty of Health, School of Medicine; Witten/Herdecke University; Cologne Germany
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21
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Penzkofer A, Luck M, Mathes T, Hegemann P. Bistable retinal schiff base photodynamics of histidine kinase rhodopsin HKR1 from Chlamydomonas reinhardtii. Photochem Photobiol 2014; 90:773-85. [PMID: 24460585 DOI: 10.1111/php.12246] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 01/21/2014] [Indexed: 11/28/2022]
Abstract
The photodynamics of the recombinant rhodopsin fragment of the histidine kinase rhodopsin HKR1 from Chlamydomonas reinhardtii was studied by absorption and fluorescence spectroscopy. The retinal cofactor of HKR1 exists in two Schiff base forms RetA and RetB. RetA is the deprotonated 13-cis-retinal Schiff base (RSB) absorbing in the UVA spectral region. RetB is the protonated all-trans RSB absorbing in the blue spectral region. Blue light exposure converts RetB fully to RetA. UVA light exposure converts RetA to RetB and RetB to RetA giving a mixture determined by their absorption cross sections and their conversion efficiencies. The quantum efficiencies of conversion of RetA to RetB and RetB to RetA were determined to be 0.096 ± 0.005 and 0.405 ± 0.01 respectively. In the dark thermal equilibration between RetA and RetB with dominant RetA content occurred with a time constant of about 3 days at room temperature. The fluorescence emission behavior of RetA and RetB was studied, and fluorescence quantum yields of ϕ(F) (RetA) = 0.00117 and ϕ(F) (RetB) = 9.4 × 10(-5) were determined. Reaction coordinate schemes of the photodynamics are developed.
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Affiliation(s)
- Alfons Penzkofer
- Fakultät für Physik, Universität Regensburg, Regensburg, Germany
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22
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Mathes T, van Stokkum IHM, Kennis JTM. Photoactivation mechanisms of flavin-binding photoreceptors revealed through ultrafast spectroscopy and global analysis methods. Methods Mol Biol 2014; 1146:401-442. [PMID: 24764100 DOI: 10.1007/978-1-4939-0452-5_16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Flavin-binding photoreceptor proteins use the isoalloxazine moiety of flavin cofactors to absorb light in the blue/UV-A wavelength region and subsequently translate it into biological information. The underlying photochemical reactions and protein structural dynamics are delicately tuned by the protein environment and represent fundamental reactions in biology and chemistry. Due to their photo-switchable nature, these proteins can be studied efficiently with laser-flash induced transient absorption and emission spectroscopy with temporal precision down to the femtosecond time domain. Here, we describe the application of both visible and mid-IR ultrafast transient absorption and time-resolved fluorescence methods in combination with sophisticated global analysis procedures to elucidate the photochemistry and signal transduction of BLUF (Blue light receptors using FAD) and LOV (Light oxygen voltage) photoreceptor domains.
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Affiliation(s)
- Tilo Mathes
- Department of Physics, Faculty of Sciences, VU University Amsterdam, De Boelelaan 1081, Amsterdam, 1081HV, The Netherlands
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23
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Mehlhorn J, Steinocher H, Beck S, Kennis JTM, Hegemann P, Mathes T. A set of engineered Escherichia coli expression strains for selective isotope and reactivity labeling of amino acid side chains and flavin cofactors. PLoS One 2013; 8:e79006. [PMID: 24223875 PMCID: PMC3815312 DOI: 10.1371/journal.pone.0079006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Accepted: 09/21/2013] [Indexed: 11/18/2022] Open
Abstract
Biological reactions are facilitated by delicate molecular interactions between proteins, cofactors and substrates. To study and understand their dynamic interactions researchers have to take great care not to influence or distort the object of study. As a non-invasive alternative to a site-directed mutagenesis approach, selective isotope labeling in combination with vibrational spectroscopy may be employed to directly identify structural transitions in wild type proteins. Here we present a set of customized Escherichia coli expression strains, suitable for replacing both the flavin cofactor and/or selective amino acids with isotope enriched or chemically modified substrates. For flavin labeling we report optimized auxotrophic strains with significantly enhanced flavin uptake properties. Labeled protein biosynthesis using these strains was achieved in optimized cultivation procedures using high cell density fermentation. Finally, we demonstrate how this approach is used for a clear assignment of vibrational spectroscopic difference signals of apoprotein and cofactor of a flavin containing photoreceptor of the BLUF (Blue Light receptors Using FAD) family.
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Affiliation(s)
- Jennifer Mehlhorn
- Institut für Biologie/Experimentelle Biophysik, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Helena Steinocher
- Institut für Biologie/Experimentelle Biophysik, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Sebastian Beck
- Institut für Chemie, Humboldt-Universität zu Berlin, Berlin, Germany
| | - John T. M. Kennis
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, Amsterdam, The Netherlands
| | - Peter Hegemann
- Institut für Biologie/Experimentelle Biophysik, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Tilo Mathes
- Institut für Biologie/Experimentelle Biophysik, Humboldt-Universität zu Berlin, Berlin, Germany
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, Amsterdam, The Netherlands
- * E-mail:
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Mathes T, Pieper D, Antoine SL, Eikermann M. Adherence-enhancing interventions for highly active antiretroviral therapy in HIV-infected patients - a systematic review. HIV Med 2013; 14:583-95. [PMID: 23773654 DOI: 10.1111/hiv.12051] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/25/2013] [Indexed: 11/28/2022]
Abstract
OBJECTIVES The objective of this systematic review was to evaluate the effectiveness of adherence-enhancing interventions for highly active antiretroviral therapy (HAART) in HIV-infected patients in developed countries. METHODS A systematic literature search was performed (January 2001 to May 2012) in EMBASE, including MEDLINE records, CENTRAL and PsycInfo. Trials meeting the following predefined inclusion criteria were included: adult patients with an HIV infection treated with HAART, an intervention to enhance patient adherence, adherence as the outcome, clinical outcomes, randomized controlled trial (RCT), article written in English or German, patient enrolment after 2001, and trial conducted in World Health Organization (WHO) stratum A. Selection was performed by two reviewers independently. All relevant data on patient characteristics, interventions, adherence measures and results were extracted in standardized tables. The methodological trial quality was evaluated by two reviewers independently. All discrepancies were discussed until a consensus was reached. A meta-analysis could not be performed because of the heterogeneity of trials. RESULTS In total, 21 trials fulfilled all inclusion criteria. Of 21 trials, only one that examined motivational interviewing for alcohol-dependent patients showed statistically significant results for adherence rates and viral load in favour of the intervention. One trial showed a statistically significant clinical effect of the intervention; however, inconsistent results were presented for adherence depending on the underlying adherence definition. The results of the remaining 19 trials were not statistically significant or were conflicting for adherence and/or clinical outcomes. However, the methodological trial quality was low. CONCLUSIONS It is not possible to definitively assess the effectiveness of adherence-enhancing interventions. However, it appears that most adherence interventions have no effect.
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Affiliation(s)
- T Mathes
- Institute for Research in Operative Medicine, Faculty of Health, School of Medicine, Witten/Herdecke University, Cologne, Germany
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25
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Langer S, Nakanishi S, Mathes T, Knaus T, Binter A, Macheroux P, Mase T, Miyakawa T, Tanokura M, Mack M. The flavoenzyme azobenzene reductase AzoR from Escherichia coli binds roseoflavin mononucleotide (RoFMN) with high affinity and is less active in its RoFMN form. Biochemistry 2013; 52:4288-95. [PMID: 23713585 DOI: 10.1021/bi400348d] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Gram-positive bacterium Streptomyces davawensis is the only organism known to produce the antibiotic roseoflavin. Roseoflavin is a structural riboflavin analogue and is converted to the flavin mononucleotide (FMN) analogue roseoflavin mononucleotide (RoFMN) by flavokinase. FMN-dependent homodimeric azobenzene reductase (AzoR) (EC 1.7.1.6) from Escherichia coli was analyzed as a model enzyme. In vivo and in vitro experiments revealed that RoFMN binds to the AzoR apoenzyme with an even higher affinity compared to that of the "natural" cofactor FMN. Structural analysis (at a resolution of 1.07 Å) revealed that RoFMN binding did not affect the overall topology of the enzyme and also did not interfere with dimerization of AzoR. The AzoR-RoFMN holoenzyme complex was found to be less active (30% of AzoR-FMN activity) in a standard assay. We provide evidence that the different physicochemical properties of RoFMN are responsible for its reduced cofactor activity.
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Affiliation(s)
- Simone Langer
- Department of Biotechnology, Institute for Technical Microbiology, Mannheim University of Applied Sciences, Germany
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26
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Zhu J, Mathes T, Stahl AD, Kennis JT, Louise Groot* M. Lower frequency region mid-infrared spectroscopy by chirped pulse upconversion. EPJ Web of Conferences 2013. [DOI: 10.1051/epjconf/20134109004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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27
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Luck M, Mathes T, Bruun S, Fudim R, Hagedorn R, Tran Nguyen TM, Kateriya S, Kennis JTM, Hildebrandt P, Hegemann P. A photochromic histidine kinase rhodopsin (HKR1) that is bimodally switched by ultraviolet and blue light. J Biol Chem 2012; 287:40083-90. [PMID: 23027869 DOI: 10.1074/jbc.m112.401604] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Rhodopsins are light-activated chromoproteins that mediate signaling processes via transducer proteins or promote active or passive ion transport as ion pumps or directly light-activated channels. Here, we provide spectroscopic characterization of a rhodopsin from the Chlamydomonas eyespot. It belongs to a recently discovered but so far uncharacterized family of histidine kinase rhodopsins (HKRs). These are modular proteins consisting of rhodopsin, a histidine kinase, a response regulator, and in some cases an effector domain such as an adenylyl or guanylyl cyclase, all encoded in a single protein as a two-component system. The recombinant rhodopsin fragment, Rh, of HKR1 is a UVA receptor (λ(max) = 380 nm) that is photoconverted by UV light into a stable blue light-absorbing meta state Rh-Bl (λ(max) = 490 nm). Rh-Bl is converted back to Rh-UV by blue light. Raman spectroscopy revealed that the Rh-UV chromophore is in an unusual 13-cis,15-anti configuration, which explains why the chromophore is deprotonated. The excited state lifetime of Rh-UV is exceptionally stable, probably caused by a relatively unpolar retinal binding pocket, converting into the photoproduct within about 100 ps, whereas the blue form reacts 100 times faster. We propose that the photochromic HKR1 plays a role in the adaptation of behavioral responses in the presence of UVA light.
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Affiliation(s)
- Meike Luck
- Institute of Biology, Experimental Biophysics, Humboldt-Universität zu Berlin, 10115 Berlin, Germany
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28
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Mathes T, Pieper D, Antoine SL, Eikermann M. Welche Faktoren beeinflussen die Patientenadhärenz in der pharmakologischen Therapie – Ein systematischer Review. Dtsch Med Wochenschr 2012. [DOI: 10.1055/s-0032-1323372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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29
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Pieper D, Mathes T, Eikermann M. Ein kritischer Beitrag zur Mindestmengendebatte aus Sicht der evidenzbasierten Medizin. Dtsch Med Wochenschr 2012. [DOI: 10.1055/s-0032-1323417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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30
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Mathes T, Pieper D, Antoine SL, Eikermann M. Adhärenzsteigernde Interventionen (AI) für die antiretrovirale Therapie (ART) bei HIV-Infizierten – Ein systematischer Review. Dtsch Med Wochenschr 2012. [DOI: 10.1055/s-0032-1323373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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31
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Pieper D, Mathes T, Eikermann M. Ein kritischer Beitrag zur Mindestmengendebatte aus Sicht der evidenzbasierten Medizin. Gesundheitswesen 2012. [DOI: 10.1055/s-0032-1322075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Mathes T, van Stokkum IHM, Stierl M, Kennis JTM. Redox modulation of flavin and tyrosine determines photoinduced proton-coupled electron transfer and photoactivation of BLUF photoreceptors. J Biol Chem 2012; 287:31725-38. [PMID: 22833672 DOI: 10.1074/jbc.m112.391896] [Citation(s) in RCA: 52] [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: 11/06/2022] Open
Abstract
Photoinduced electron transfer in biological systems, especially in proteins, is a highly intriguing matter. Its mechanistic details cannot be addressed by structural data obtained by crystallography alone because this provides only static information on a given redox system. In combination with transient spectroscopy and site-directed manipulation of the protein, however, a dynamic molecular picture of the ET process may be obtained. In BLUF (blue light sensors using FAD) photoreceptors, proton-coupled electron transfer between a tyrosine and the flavin cofactor is the key reaction to switch from a dark-adapted to a light-adapted state, which corresponds to the biological signaling state. Particularly puzzling is the fact that, although the various naturally occurring BLUF domains show little difference in the amino acid composition of the flavin binding pocket, the reaction rates of the forward reaction differ quite largely from a few ps up to several hundred ps. In this study, we modified the redox potential of the flavin/tyrosine redox pair by site-directed mutagenesis close to the flavin C2 carbonyl and fluorination of the tyrosine, respectively. We provide information on how changes in the redox potential of either reaction partner significantly influence photoinduced proton-coupled electron transfer. The altered redox potentials allowed us furthermore to experimentally describe an excited state charge transfer intermediately prior to electron transfer in the BLUF photocycle. Additionally, we show that the electron transfer rate directly correlates with the quantum yield of signaling state formation.
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Affiliation(s)
- Tilo Mathes
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081A, 1081 HV, Amsterdam, The Netherlands.
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Zhu J, Mathes T, Stahl AD, Kennis JTM, Groot ML. Ultrafast mid-infrared spectroscopy by chirped pulse upconversion in 1800-1000cm(-1) region. Opt Express 2012; 20:10562-10571. [PMID: 22565682 DOI: 10.1364/oe.20.010562] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Broadband femtosecond mid-infrared pulses can be converted into the visible spectral region by chirped pulse upconversion. We report here the upconversion of pump probe transient signals in the frequency region below 1800cm(-1), using the nonlinear optical crystal AgGaGeS4, realizing an important expansion of the application range of this method. Experiments were demonstrated with a slab of GaAs, in which the upconverted signals cover a window of 120cm(-1), with 1.5cm(-1) resolution. In experiments on the BLUF photoreceptor Slr1694, signals below 1 milliOD were well resolved after baseline correction. Possibilities for further optimization of the method are discussed. We conclude that this method is an attractive alternative for the traditional MCT arrays used in most mid-infrared pump probe experiments.
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Affiliation(s)
- Jingyi Zhu
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, Amsterdam, The Netherlands
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Mathes T, van Stokkum IHM, Bonetti C, Hegemann P, Kennis JTM. The Hydrogen-Bond Switch Reaction of the Blrb Bluf Domain of Rhodobacter sphaeroides. J Phys Chem B 2011; 115:7963-71. [DOI: 10.1021/jp201296m] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Tilo Mathes
- Institut für Biologie/Experimentelle Biophysik, Humboldt Universität zu Berlin, Invalidenstrasse 42, D-10115 Berlin, Germany
| | - Ivo H. M. van Stokkum
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Cosimo Bonetti
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Peter Hegemann
- Institut für Biologie/Experimentelle Biophysik, Humboldt Universität zu Berlin, Invalidenstrasse 42, D-10115 Berlin, Germany
| | - John T. M. Kennis
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
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Weber S, Schroeder C, Kacprzak S, Mathes T, Kowalczyk RM, Essen LO, Hegemann P, Schleicher E, Bittl R. Light-generated paramagnetic intermediates in BLUF domains. Photochem Photobiol 2011; 87:574-83. [PMID: 21198648 DOI: 10.1111/j.1751-1097.2010.00885.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Blue-light sensitive photoreceptory BLUF domains are flavoproteins, which regulate various, mostly stress-related processes in bacteria and eukaryotes. The photoreactivity of the flavin adenine dinucleotide (FAD) cofactor in three BLUF domains from Rhodobacter sphaeroides, Synechocystis sp. PCC 6803 and Escherichia coli have been studied at low temperature using time-resolved electron paramagnetic resonance. Photoinduced flavin triplet states and radical-pair species have been detected on a microsecond time scale. Differences in the electronic structures of the FAD cofactors as reflected by altered zero-field splitting parameters of the triplet states could be correlated with changes in the amino-acid composition of the various BLUF domains' cofactor binding pockets. For the generation of the light-induced, spin-correlated radical-pair species in the BLUF domain from Synechocystis sp. PCC 6803, a tyrosine residue near the flavin's isoalloxazine moiety plays a critical role.
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Affiliation(s)
- Stefan Weber
- Albert-Ludwigs-Universität Freiburg, Institut für Physikalische Chemie, Freiburg, Germany
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Brosi R, Illarionov B, Mathes T, Fischer M, Joshi M, Bacher A, Hegemann P, Bittl R, Weber S, Schleicher E. Hindered rotation of a cofactor methyl group as a probe for protein-cofactor interaction. J Am Chem Soc 2010; 132:8935-44. [PMID: 20536240 DOI: 10.1021/ja910681z] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Exploring protein-cofactor interactions on a molecular level is one of the major challenges in modern biophysics. Based on structural data alone it is rarely possible to identify how subtle interactions between a protein and its cofactor modulate the protein's reactivity. In the case of enzymatic processes in which paramagnetic molecules play a certain role, EPR and related methods such as ENDOR are suitable techniques to unravel such important details. In this contribution, we describe how cryogenic-temperature ENDOR spectroscopy can be applied to various LOV domains, the blue-light sensing domains of phototropin photoreceptors, to gain information on the direct vicinity of the flavin mononucleotide (FMN) cofactor by analyzing the temperature dependence of methyl-group rotation attached to C(8) of the FMN's isoalloxazine ring. More specifically, mutational studies of three amino acids surrounding the methyl group led to the identification of Asn425 as an important amino acid that critically influences the dark-state recovery of Avena sativa LOV2 domains. Consequently, it is possible to probe protein-cofactor interactions on a sub-angstrom level by following the temperature dependencies of hyperfine couplings.
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Affiliation(s)
- Richard Brosi
- Fachbereich Physik, Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany
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Tyagi A, Penzkofer A, Mathes T, Hegemann P. Photophysical characterisation and photo-cycle dynamics of LOV1-His domain of phototropin from Chlamydomonas reinhardtii with roseoflavin monophosphate cofactor. J Photochem Photobiol B 2010; 101:76-88. [PMID: 20655238 DOI: 10.1016/j.jphotobiol.2010.06.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 06/29/2010] [Accepted: 06/29/2010] [Indexed: 11/19/2022]
Abstract
The wild-type phototropin protein phot from the green alga Chlamydomonas reinhardtii with the blue-light photoreceptor domains LOV1 and LOV2 has flavin mononucleotide (FMN) as cofactor. For the LOV1-His domain from phot of C. reinhardtii studied here, the FMN chromophore was replaced by roseoflavin monophosphate (8-dimethylamino-8-demethyl-FMN, RoFMN) during heterologous expression in a riboflavin auxotropic Escherichia coli strain. An absorption and emission spectroscopic characterisation of the cofactor exchanged-LOV1-His (RoLOV1) domain was carried out in aqueous pH 8 phosphate buffer. The fluorescence of RoLOV1 is quenched by photo-induced charge transfer at room temperature. The photo-cyclic dynamics of RoLOV1 was observed by blue-light induced hypochromic and bathochromic absorption changes which recover on a minute timescale in the dark. Photo-excited RoFMN is thought to cause reversible protein and cofactor structural changes. Prolonged intense blue-light exposure caused photo-degradation of RoFMN in RoLOV1 to fully reduced flavin and lumichrome derivatives. Photo-cycle schemes of RoLOV1 and LOV1 are presented, and the photo-degradation dynamics of RoLOV1 is discussed.
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Affiliation(s)
- A Tyagi
- Fakultät für Physik, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany
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Pfeifer A, Mathes T, Lu Y, Hegemann P, Kottke T. Blue Light Induces Global and Localized Conformational Changes in the Kinase Domain of Full-Length Phototropin. Biochemistry 2010; 49:1024-32. [DOI: 10.1021/bi9016044] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Anna Pfeifer
- Department of Chemistry, Biophysical Chemistry, Bielefeld University, Universitätsstrasse 25, 33615 Bielefeld, Germany
| | - Tilo Mathes
- Institut für Biologie, Experimentelle Biophysik, Humboldt Universität zu Berlin, Invalidenstrasse 42, 10115 Berlin, Germany
| | - Yinghong Lu
- Institut für Biologie, Experimentelle Biophysik, Humboldt Universität zu Berlin, Invalidenstrasse 42, 10115 Berlin, Germany
| | - Peter Hegemann
- Institut für Biologie, Experimentelle Biophysik, Humboldt Universität zu Berlin, Invalidenstrasse 42, 10115 Berlin, Germany
| | - Tilman Kottke
- Department of Chemistry, Biophysical Chemistry, Bielefeld University, Universitätsstrasse 25, 33615 Bielefeld, Germany
- Institute of Structural Biology and Biophysics 2, Research Center Jülich, 52425 Jülich, Germany
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Bonetti C, Stierl M, Mathes T, van Stokkum IHM, Mullen KM, Cohen-Stuart TA, van Grondelle R, Hegemann P, Kennis JTM. The role of key amino acids in the photoactivation pathway of the Synechocystis Slr1694 BLUF domain. Biochemistry 2009; 48:11458-69. [PMID: 19863128 DOI: 10.1021/bi901196x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BLUF (blue light sensing using FAD) domains belong to a novel group of blue light sensing receptor proteins found in microorganisms. We have assessed the role of specific aromatic and polar residues in the Synechocystis Slr1694 BLUF protein by investigating site-directed mutants with substitutions Y8W, W91F, and S28A. The W91F and S28A mutants formed the red-shifted signaling state upon blue light illumination, whereas in the Y8W mutant, signaling state formation was abolished. The W91F mutant shows photoactivation dynamics that involve the successive formation of FAD anionic and neutral semiquinone radicals on a picosecond time scale, followed by radical pair recombination to result in the long-lived signaling state in less than 100 ps. The photoactivation dynamics and quantum yield of signaling state formation were essentially identical to those of wild type, which indicates that only one significant light-driven electron transfer pathway is available in Slr1694, involving electron transfer from Y8 to FAD without notable contribution of W91. In the S28A mutant, the photoactivation dynamics and quantum yield of signaling state formation as well as dark recovery were essentially the same as in wild type. Thus, S28 does not play an essential role in the initial hydrogen bond switching reaction in Slr1694 beyond an influence on the absorption spectrum. In the Y8W mutant, two deactivation branches upon excitation were identified: the first involves a neutral semiquinone FADH(*) that was formed in approximately 1 ps and recombines in 10 ps and is tentatively assigned to a FADH(*)-W8(*) radical pair. The second deactivation branch forms FADH(*) in 8 ps and evolves to FAD(*-) in 200 ps, which recombines to the ground state in about 4 ns. In the latter branch, W8 is tentatively assigned as the FAD redox partner as well. Overall, the results are consistent with a photoactivation mechanism for BLUF domains where signaling state formation proceeds via light-driven electron and proton transfer from Y8 to FAD, followed by a hydrogen bond rearrangement and radical pair recombination.
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Affiliation(s)
- Cosimo Bonetti
- Biophysics Group, Department of Physics and Astronomy, Faculty of Sciences, VU University, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
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Zirak P, Penzkofer A, Mathes T, Hegemann P. Absorption and emission spectroscopic characterization of BLUF protein Slr1694 from Synechocystis sp. PCC6803 with roseoflavin cofactor. Journal of Photochemistry and Photobiology B: Biology 2009; 97:61-70. [DOI: 10.1016/j.jphotobiol.2009.08.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2009] [Revised: 07/08/2009] [Accepted: 08/04/2009] [Indexed: 10/20/2022]
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Tyagi A, Zirak P, Penzkofer A, Mathes T, Hegemann P, Mack M, Ghisla S. Absorption and emission spectroscopic characterisation of 8-amino-riboflavin. Chem Phys 2009. [DOI: 10.1016/j.chemphys.2009.08.005] [Citation(s) in RCA: 7] [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: 10/20/2022]
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Mathes T, Vogl C, Stolz J, Hegemann P. In Vivo Generation of Flavoproteins with Modified Cofactors. J Mol Biol 2009; 385:1511-8. [DOI: 10.1016/j.jmb.2008.11.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2008] [Revised: 10/31/2008] [Accepted: 11/03/2008] [Indexed: 10/21/2022]
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Zirak P, Penzkofer A, Lehmpfuhl C, Mathes T, Hegemann P. Absorption and emission spectroscopic characterization of blue-light receptor Slr1694 from Synechocystis sp. PCC6803. J Photochem Photobiol B 2006; 86:22-34. [PMID: 16996275 DOI: 10.1016/j.jphotobiol.2006.08.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2006] [Revised: 08/08/2006] [Accepted: 08/08/2006] [Indexed: 11/22/2022]
Abstract
The BLUF protein Slr1694 from the cyanobacterium Synechocystis sp. PCC6803 is characterized by absorption and emission spectroscopy. Slr1694 expressed from E. coli which non-covalently binds FAD, FMN, and riboflavin (called Slr1694(I)), and reconstituted Slr1694 which dominantly contains FAD (called Slr1694(II)) are investigated. The receptor conformation of Slr1694 (dark adapted form Slr1694(r)) is transformed to the putative signalling state (light adapted form Slr1694(s)) with red-shifted absorption and decreased fluorescence efficiency by blue-light excitation. In the dark at 22 degrees C, the signalling state recovers back to the initial receptor state with a time constants of about 14.2s for Slr1694(I) and 17s for Slr1694(II). Quantum yields of signalling state formation of approximately 0.63+/-0.07 for both Slr1694(I) and Slr1694(II) were determined by transient transmission measurements and intensity dependent steady-state transmission measurements. Extended blue-light excitation causes some bound flavin conversion to the hydroquinone form and some photo-degradation, both with low quantum efficiency. The flavin-hydroquinone re-oxidizes slowly back (time constant 5-9 min) to the initial flavoquinone form in the dark. A photo-cycle dynamics scheme is presented.
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Affiliation(s)
- P Zirak
- Institut II - Experimentelle und Angewandte Physik, Universität Regensburg, Universitätstrasse 31, D-93053 Regensburg, Germany
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