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Amado D, Chaves OA, Cruz PF, Loureiro RJS, Almeida ZL, Jesus CSH, Serpa C, Brito RMM. Folding Kinetics and Volume Variation of the β-Hairpin Peptide Chignolin upon Ultrafast pH-Jumps. J Phys Chem B 2024; 128:4898-4910. [PMID: 38733339 DOI: 10.1021/acs.jpcb.3c08271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2024]
Abstract
In-depth characterization of fundamental folding steps of small model peptides is crucial for a better understanding of the folding mechanisms of more complex biomacromolecules. We have previously reported on the folding/unfolding kinetics of a model α-helix. Here, we study folding transitions in chignolin (GYDPETGTWG), a short β-hairpin peptide previously used as a model to study conformational changes in β-sheet proteins. Although previously suggested, until now, the role of the Tyr2-Trp9 interaction in the folding mechanism of chignolin was not clear. In the present work, pH-dependent conformational changes of chignolin were characterized by circular dichroism (CD), nuclear magnetic resonance (NMR), ultrafast pH-jump coupled with time-resolved photoacoustic calorimetry (TR-PAC), and molecular dynamics (MD) simulations. Taken together, our results present a comprehensive view of chignolin's folding kinetics upon local pH changes and the role of the Tyr2-Trp9 interaction in the folding process. CD data show that chignolin's β-hairpin formation displays a pH-dependent skew bell-shaped curve, with a maximum close to pH 6, and a large decrease in β-sheet content at alkaline pH. The β-hairpin structure is mainly stabilized by aromatic interactions between Tyr2 and Trp9 and CH-π interactions between Tyr2 and Pro4. Unfolding of chignolin at high pH demonstrates that protonation of Tyr2 is essential for the stability of the β-hairpin. Refolding studies were triggered by laser-induced pH-jumps and detected by TR-PAC. The refolding of chignolin from high pH, mainly due to the protonation of Tyr2, is characterized by a volume expansion (10.4 mL mol-1), independent of peptide concentration, in the microsecond time range (lifetime of 1.15 μs). At high pH, the presence of the deprotonated hydroxyl (tyrosinate) hinders the formation of the aromatic interaction between Tyr2 and Trp9 resulting in a more disorganized and dynamic tridimensional structure of the peptide. This was also confirmed by comparing MD simulations of chignolin under conditions mimicking neutral and high pH.
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Affiliation(s)
- Daniela Amado
- CQC-IMS, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Otávio A Chaves
- CQC-IMS, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Pedro F Cruz
- CQC-IMS, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Rui J S Loureiro
- CQC-IMS, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Zaida L Almeida
- CQC-IMS, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Catarina S H Jesus
- CQC-IMS, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Carlos Serpa
- CQC-IMS, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Rui M M Brito
- CQC-IMS, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
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2
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Karlsson JKG, Atahan A, Harriman A, Tkachenko NV, Ward AD, Schaberle FA, Serpa C, Arnaut LG. Singlet Exciton Fission and Associated Enthalpy Changes with a Covalently Linked Bichromophore Comprising TIPS-Pentacenes Held in an Open Conformation. J Phys Chem A 2021; 125:1184-1197. [DOI: 10.1021/acs.jpca.0c09961] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Joshua K. G. Karlsson
- Molecular Photonics Laboratory, School of Natural and Environmental Sciences, Newcastle University, Bedson Building, Newcastle upon Tyne NE1 7RU, U.K
| | - Alparslan Atahan
- Molecular Photonics Laboratory, School of Natural and Environmental Sciences, Newcastle University, Bedson Building, Newcastle upon Tyne NE1 7RU, U.K
| | - Anthony Harriman
- Molecular Photonics Laboratory, School of Natural and Environmental Sciences, Newcastle University, Bedson Building, Newcastle upon Tyne NE1 7RU, U.K
| | - Nikolai V. Tkachenko
- Faculty of Engineering and Natural Sciences, Tampere University, Koereakoulunkatu 7, FIN-33720 Tampere, Finland
| | - Andrew D. Ward
- Central Laser Facility, Research Complex at Harwell, STFC Rutherford Appleton Laboratory, Didcot OX11 0FA, U.K
| | - Fabio A. Schaberle
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Carlos Serpa
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
| | - Luis G. Arnaut
- CQC, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal
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3
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Henriques J, Schaberle FA, Serpa C, Pais AACC, Cardoso C, Vitorino C. Photoacoustic method for real-time assessment of salt content in aqueous solutions. Talanta 2021; 222:121497. [PMID: 33167211 DOI: 10.1016/j.talanta.2020.121497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/26/2020] [Accepted: 07/30/2020] [Indexed: 11/26/2022]
Abstract
In 2004, the Food and Drug Administration established the foundations for the application of process analytical technologies (PAT) in real-time control of the drug manufacturing process, where progress has been essentially directed to solid formulations. In order to enlarge the application of PAT principles to injectable drug products, the development of appropriate manufacturing process control tools is mandatory. Photoacoustics is a non-invasive technique with the potential for application in real-time control of the manufacturing process of injectable drug products. Herein, we applied a photoacoustic method for the determination of the concentration of salts (sodium chloride) in mono-salt formulations by measuring the changes induced in the speed of sound by density changes. This method was explored using two modes of generating the photoacoustic wave and two detectors with central frequencies of 10 MHz and 100 MHz. The results were analyzed using a 2k full-factorial design, considering the generation mode and detection as independent variables. The optimized method was subsequently validated according to the International Council for Harmonisation (ICH) standards. The method showed good linearity, precision, and accuracy, with a lower limit of quantification of 0.05% (w/v) of NaCl and a limit of detection of 0.02% (w/v) of NaCl. Due to its simplicity and high throughput, this method has potential applicability as PAT in the manufacturing of injectable drug products.
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Affiliation(s)
- João Henriques
- Faculty of Pharmacy, University of Coimbra, Pólo Das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548, Coimbra, Portugal; CQC, Department of Chemistry, University of Coimbra, Rua Larga, 3004-535, Coimbra, Portugal
| | - Fábio A Schaberle
- CQC, Department of Chemistry, University of Coimbra, Rua Larga, 3004-535, Coimbra, Portugal
| | - Carlos Serpa
- CQC, Department of Chemistry, University of Coimbra, Rua Larga, 3004-535, Coimbra, Portugal
| | - Alberto A C C Pais
- CQC, Department of Chemistry, University of Coimbra, Rua Larga, 3004-535, Coimbra, Portugal
| | - Catarina Cardoso
- Laboratórios Basi, Parque Industrial Manuel Lourenço Ferreira, lote 15, 3450-232, Mortágua, Portugal
| | - Carla Vitorino
- Faculty of Pharmacy, University of Coimbra, Pólo Das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548, Coimbra, Portugal; CQC, Department of Chemistry, University of Coimbra, Rua Larga, 3004-535, Coimbra, Portugal; Center for Neurosciences and Cell Biology (CNC), University of Coimbra, Rua Larga, Faculty of Medicine, Pólo I, 1st Floor, 3004-504, Coimbra, Portugal.
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Fuenzalida Werner JP, Huang Y, Mishra K, Janowski R, Vetschera P, Heichler C, Chmyrov A, Neufert C, Niessing D, Ntziachristos V, Stiel AC. Challenging a Preconception: Optoacoustic Spectrum Differs from the Optical Absorption Spectrum of Proteins and Dyes for Molecular Imaging. Anal Chem 2020; 92:10717-10724. [PMID: 32640156 DOI: 10.1021/acs.analchem.0c01902] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Optoacoustic (photoacoustic) imaging has seen marked advances in detection and data analysis, but there is less progress in understanding the photophysics of common optoacoustic contrast agents. This gap blocks the development of novel agents and the accurate analysis and interpretation of multispectral optoacoustic images. To close it, we developed a multimodal laser spectrometer (MLS) to enable the simultaneous measurement of optoacoustic, absorbance, and fluorescence spectra. Herein, we employ MLS to analyze contrast agents (methylene blue, rhodamine 800, Alexa Fluor 750, IRDye 800CW, and indocyanine green) and proteins (sfGFP, mCherry, mKate, HcRed, iRFP720, and smURFP). We found that the optical absorption spectrum does not correlate with the optoacoustic spectrum for the majority of the analytes. We determined that for dyes, the transition underlying an aggregation state has more optoacoustic signal generation efficiency than the monomer transition. For proteins we found a favored optoacoustic relaxation that stems from the neutral or zwitterionic chromophores and unreported photoswitching behavior of tdTomato and HcRed. We then crystalized HcRed in its photoswitch optoacoustic state, confirming structurally the change in isomerization with respect to HcReds' fluorescence state. Finally, on the example of the widely used label tdTomato and the dye indocyanine green, we show the importance of correct photophysical (e.g., spectral and kinetic) information as a prerequisite for spectral-unmixing for in vivo imaging.
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Affiliation(s)
| | - Yuanhui Huang
- Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, D-85764 Neuherberg, Germany.,Chair of Biological Imaging, Technische Universitat München, D-81675 Munich, Germany
| | - Kanuj Mishra
- Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, D-85764 Neuherberg, Germany.,Chair of Biological Imaging, Technische Universitat München, D-81675 Munich, Germany
| | - Robert Janowski
- Intracellular Transport and RNA Biology Group, Institute of Structural Biology, Helmholtz Zentrum München, D-85764 Neuherberg, Germany
| | - Paul Vetschera
- Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, D-85764 Neuherberg, Germany.,Chair of Biological Imaging, Technische Universitat München, D-81675 Munich, Germany
| | - Christina Heichler
- First Department of Medicine, Universitaetsklinikum Erlangen, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, D-89081 Erlangen, Germany
| | - Andriy Chmyrov
- Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, D-85764 Neuherberg, Germany.,Chair of Biological Imaging, Technische Universitat München, D-81675 Munich, Germany.,Center for Translational Cancer Research (TranslaTUM), Technische Universitat München, D-81675 Munich, Germany
| | - Clemens Neufert
- First Department of Medicine, Universitaetsklinikum Erlangen, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, D-89081 Erlangen, Germany
| | - Dierk Niessing
- Intracellular Transport and RNA Biology Group, Institute of Structural Biology, Helmholtz Zentrum München, D-85764 Neuherberg, Germany.,Institute of Pharmaceutical Biotechnology, Ulm University, 89081 Ulm, Germany
| | - Vasilis Ntziachristos
- Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, D-85764 Neuherberg, Germany.,Chair of Biological Imaging, Technische Universitat München, D-81675 Munich, Germany.,Center for Translational Cancer Research (TranslaTUM), Technische Universitat München, D-81675 Munich, Germany
| | - Andre C Stiel
- Institute of Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, D-85764 Neuherberg, Germany
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5
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The Photophysical Properties of Triisopropylsilyl-ethynylpentacene—A Molecule with an Unusually Large Singlet-Triplet Energy Gap—In Solution and Solid Phases. CHEMISTRY-SWITZERLAND 2020. [DOI: 10.3390/chemistry2020033] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The process of singlet-exciton fission (SEF) has attracted much attention of late. One of the most popular SEF compounds is TIPS-pentacene (TIPS-P, where TIPS = triisopropylsilylethynyl) but, despite its extensive use as both a reference and building block, its photophysical properties are not so well established. In particular, the triplet state excitation energy remains uncertain. Here, we report quantitative data and spectral characterization for excited-singlet and -triplet states in dilute solution. The triplet energy is determined to be 7940 ± 1200 cm−1 on the basis of sensitization studies using time-resolved photoacoustic calorimetry. The triplet quantum yield at the limit of low concentration and low laser intensity is only ca. 1%. Self-quenching occurs at high solute concentration where the fluorescence yield and lifetime decrease markedly relative to dilute solution but we were unable to detect excimer emission by steady-state spectroscopy. Short-lived fluorescence, free from excimer emission or phosphorescence, occurs for crystals of TIPS-P, most likely from amorphous domains.
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6
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Mishra K, Fuenzalida-Werner JP, Ntziachristos V, Stiel AC. Photocontrollable Proteins for Optoacoustic Imaging. Anal Chem 2019; 91:5470-5477. [PMID: 30933491 DOI: 10.1021/acs.analchem.9b01048] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Photocontrollable proteins revolutionized life-science imaging due to their contribution to subdiffraction-resolution optical microscopy. They might have yet another lasting impact on photo- or optoacoustic imaging (OA). OA combines optical contrast with ultrasound detection enabling high-resolution real-time in vivo imaging well-beyond the typical penetration depth of optical methods. While OA already showed numerous applications relying on endogenous contrast from blood hemoglobin or lipids, its application in the life-science was limited by a lack of labels overcoming the strong signal from the aforementioned endogenous absorbers. Here, a number of recent studies showed that photocontrollable proteins provide the means to overcome this barrier eventually enabling OA to image small cell numbers in a complete organism in vivo. In this Feature article, we introduce the key photocontrollable proteins, explain the basic concepts, and highlight achievements that have been already made.
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Affiliation(s)
- Kanuj Mishra
- Institute of Biological and Medical Imaging (IBMI) , Helmholtz Zentrum München , 85764 Neuherberg , Germany
| | | | - Vasilis Ntziachristos
- Institute of Biological and Medical Imaging (IBMI) , Helmholtz Zentrum München , 85764 Neuherberg , Germany.,Chair of Biological Imaging and Center for Translational Cancer Research (TranslaTUM) , Technische Universität München , 81675 Munich , Germany
| | - Andre C Stiel
- Institute of Biological and Medical Imaging (IBMI) , Helmholtz Zentrum München , 85764 Neuherberg , Germany
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7
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Chaves OA, Jesus CSH, Henriques ES, Brito RMM, Serpa C. In situ ultra-fast heat deposition does not perturb the structure of serum albumin. Photochem Photobiol Sci 2018; 15:1524-1535. [PMID: 27841431 DOI: 10.1039/c6pp00209a] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
MnTPPS is a metallic water soluble porphyrin with high potential to be used as a contrast agent in photoacoustic tomography. In order to fully understand the interaction between MnTPPS and serum albumin and to investigate the effect of the light induced fast in situ heat deposition by MnTPPS in the protein, we performed several experimental studies using fluorescence and circular dichroism spectroscopies, as well as photoacoustic calorimetry. To identify the possible binding site(s) of the metalloporphyrin in serum albumin and to help interpret the spectroscopic results, a molecular docking exercise was also carried out. The fluorescence data indicate a 1 : 1 stoichiometry for the complex BSA : MnTPPS. The molecular docking results suggest one binding site at the subdomain IB of albumin, where Trp-134 is found, as the main binding site for MnTPPS. The CD data indicate no significant conformational changes of the BSA secondary structure upon MnTPPS binding and even after several minutes of laser excitation of MnTPPS. TR-PAC results show that the in situ heat deposition from MnTPPS does not cause any significant transient conformational change to the BSA structure. In conclusion, this work demonstrates that MnTPPS, in addition to the necessary physical and chemical properties to be used as a contrast agent in photoacoustic tomography, can be effectively carried by albumin and that in situ heat release following light absorption does not cause any significant damage to the protein structure.
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Affiliation(s)
- Otávio A Chaves
- ICE, Chemistry Department, Universidade Federal Rural do Rio de Janeiro, 23890-000, Seropédica-RJ, Brazil and CQC, Chemistry Department, University of Coimbra, 3004-535, Coimbra, Portugal.
| | - Catarina S H Jesus
- CQC, Chemistry Department, University of Coimbra, 3004-535, Coimbra, Portugal.
| | - Elsa S Henriques
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-535, Coimbra, Portugal
| | - Rui M M Brito
- CQC, Chemistry Department, University of Coimbra, 3004-535, Coimbra, Portugal.
| | - Carlos Serpa
- CQC, Chemistry Department, University of Coimbra, 3004-535, Coimbra, Portugal.
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8
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Schaberle FA, Abreu AR, Gonçalves NPF, Sá GFF, Pereira MM, Arnaut LG. Ultrafast Dynamics of Manganese(III), Manganese(II), and Free-Base Bacteriochlorin: Is There Time for Photochemistry? Inorg Chem 2017; 56:2677-2689. [PMID: 28206747 DOI: 10.1021/acs.inorgchem.6b02871] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Manganese(III) and manganese(II) complexes of halogenated sulfonamide tetraphenylbacteriochlorins were prepared for the first time via a transmetalation reaction and shown to be stable at room temperature. The behavior of the electronic states of the paramagnetic complexes is remarkably different from those of the metal-free bacteriochlorins or diamagnetic metallobacteriochlorins. The Mn3+ complex exhibits eight electronic transitions between different states from 300 to 1100 nm, with a very prominent band (molar absorption coefficient of ca. 50000 M-1 cm-1) at 829 nm. Ultrafast transient absorption showed the formation of an excited singquintet state that decays to a tripquintet state with a femtosecond lifetime. The tripquintet state decays in 5 ps, yielding a tripseptet state with a 570 ps lifetime. The electronic absorption of the Mn2+ complex more closely resembles those of diamagnetic metallobacteriochlorins, but the longest decay lifetime is only ca. 8 ps. The intense photoacoustic waves generated with near-infrared excitation suggest the use of these complexes in photoacoustic tomography.
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Affiliation(s)
- Fabio A Schaberle
- Luzitin SA, Ed. Bluepharma , S. Martinho do Bispo, 3045-016 Coimbra, Portugal.,Chemistry Department, University of Coimbra , 3004-535 Coimbra, Portugal
| | - Artur R Abreu
- Luzitin SA, Ed. Bluepharma , S. Martinho do Bispo, 3045-016 Coimbra, Portugal
| | - Nuno P F Gonçalves
- Luzitin SA, Ed. Bluepharma , S. Martinho do Bispo, 3045-016 Coimbra, Portugal
| | - Gonçalo F F Sá
- LaserLeap SA, IPN , R. Pedro Nunes, 3030-199 Coimbra, Portugal
| | - Mariette M Pereira
- Chemistry Department, University of Coimbra , 3004-535 Coimbra, Portugal
| | - Luís G Arnaut
- Chemistry Department, University of Coimbra , 3004-535 Coimbra, Portugal
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