1
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Zhou M, González PJ, Van Haasterecht L, Soylu A, Mihailovski M, Van Zuijlen P, Groot ML. Uniaxial mechanical stretch properties correlated with three-dimensional microstructure of human dermal skin. Biomech Model Mechanobiol 2024:10.1007/s10237-023-01813-3. [PMID: 38324073 DOI: 10.1007/s10237-023-01813-3] [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] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 12/30/2023] [Indexed: 02/08/2024]
Abstract
The intact and healthy skin forms a barrier to the outside world and protects the body from mechanical impact. The skin is a complex structure with unique mechano-elastic properties. To better direct the design of biomimetic materials and induce skin regeneration in wounds with optimal outcome, more insight is required in how the mechano-elastic properties emerge from the skin's main constituents, collagen and elastin fibers. Here, we employed two-photon excited autofluorescence and second harmonic generation microscopy to characterize collagen and elastin fibers in 3D in 24 human dermis skin samples. Through uniaxial stretching experiments, we derive uni-directional mechanical properties from resultant stress-strain curves, including the initial Young's modulus, elastic Young's modulus, maximal stress, and maximal and mid-strain values. The stress-strain curves show a large variation, with an average Young's modules in the toe and linear regions of 0.1 MPa and 21 MPa. We performed a comprehensive analysis of the correlation between the key mechanical properties with age and with microstructural parameters, e.g., fiber density, thickness, and orientation. Age was found to correlate negatively with Young's modulus and collagen density. Moreover, real-time monitoring during uniaxial stretching allowed us to observe changes in collagen and elastin alignment. Elastin fibers aligned significantly in both the heel and linear regions, and the collagen bundles engaged and oriented mainly in the linear region. This research advances our understanding of skin biomechanics and yields input for future first principles full modeling of skin tissue.
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Affiliation(s)
- Mengyao Zhou
- Faculty of Science, Department of Physics, Laserlab, Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081HV, Amsterdam, The Netherlands.
| | - Patrick José González
- Faculty of Science, Department of Physics, Laserlab, Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081HV, Amsterdam, The Netherlands
| | - Ludo Van Haasterecht
- Faculty of Science, Department of Physics, Laserlab, Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081HV, Amsterdam, The Netherlands
- Burn Center and Department of Plastic, Reconstructive and Hand Surgery, Red Cross Hospital, Mozartstraat 201, 1962 AB, Beverwijk, The Netherlands
- Department of Plastic, Reconstructive and Hand Surgery, Amsterdam University Medical Center (UMC), Location Vrije Universiteit Amsterdam, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Alperen Soylu
- Faculty of Science, Department of Physics, Laserlab, Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081HV, Amsterdam, The Netherlands
| | - Maria Mihailovski
- Faculty of Science, Department of Physics, Laserlab, Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081HV, Amsterdam, The Netherlands
| | - Paul Van Zuijlen
- Burn Center and Department of Plastic, Reconstructive and Hand Surgery, Red Cross Hospital, Mozartstraat 201, 1962 AB, Beverwijk, The Netherlands
- Department of Plastic, Reconstructive and Hand Surgery, Amsterdam University Medical Center (UMC), Location Vrije Universiteit Amsterdam, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
- Pediatric Surgical Centre, Emma Children's Hospital, Amsterdam University Medical Center (UMC), Location University of Amsterdam, Meibergdreef 9, Amsterdam, The Netherlands
- Amsterdam Movement Sciences (AMS) Institute, Amsterdam University Medical Center (UMC), Location Vrije Universiteit Amsterdam, Meibergdreef 9, Amsterdam, The Netherlands
| | - Marie Louise Groot
- Faculty of Science, Department of Physics, Laserlab, Vrije Universiteit Amsterdam, De Boelelaan 1105, 1081HV, Amsterdam, The Netherlands
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2
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Kok SD, Schaap PMR, van Dommelen L, van Huizen LMG, Dickhoff C, Dijkum EMNV, Engelsman AF, van der Valk P, Groot ML. Compact portable higher harmonic generation microscopy for the real time assessment of unprocessed thyroid tissue. J Biophotonics 2024; 17:e202300079. [PMID: 37725434 DOI: 10.1002/jbio.202300079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 09/12/2023] [Accepted: 09/15/2023] [Indexed: 09/21/2023]
Abstract
During thyroid surgery fast and reliable intra-operative pathological feedback has the potential to avoid a two-stage procedure and significantly reduce health care costs in patients undergoing a diagnostic hemithyroidectomy (HT). We explored higher harmonic generation (HHG) microscopy, which combines second harmonic generation (SHG), third harmonic generation (THG), and multiphoton excited autofluorescence (MPEF) for this purpose. With a compact, portable HHG microscope, images of freshly excised healthy tissue, benign nodules (follicular adenoma) and malignant tissue (papillary carcinoma, follicular carcinoma and spindle cell carcinoma) were recorded. The images were generated on unprocessed tissue within minutes and show relevant morphological thyroid structures in good accordance with the histology images. The thyroid follicle architecture, cells, cell nuclei (THG), collagen organization (SHG) and the distribution of thyroglobulin and/or thyroid hormones T3 or T4 (MPEF) could be visualized. We conclude that SHG/THG/MPEF imaging is a promising tool for clinical intraoperative assessment of thyroid tissue.
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Affiliation(s)
- S D Kok
- Vrije Universiteit Amsterdam, Faculty of Science, Department of Physics, LaserLab, Amsterdam, The Netherlands
| | - P M Rodriguez Schaap
- Department of Surgery, Amsterdam UMC, location VUmc, Amsterdam, The Netherlands
- Cancer Center Amsterdam, Amsterdam UMC, Amsterdam, The Netherlands
| | - L van Dommelen
- Department of Surgery, Amsterdam UMC, location VUmc, Amsterdam, The Netherlands
| | - L M G van Huizen
- Vrije Universiteit Amsterdam, Faculty of Science, Department of Physics, LaserLab, Amsterdam, The Netherlands
| | - C Dickhoff
- Department of Surgery, Amsterdam UMC, location VUmc, Amsterdam, The Netherlands
- Cancer Center Amsterdam, Amsterdam UMC, Amsterdam, The Netherlands
- Department of Cardiothoracic Surgery, Amsterdam UMC, location VUmc, Amsterdam, The Netherlands
| | - E M Nieveen-van Dijkum
- Department of Surgery, Amsterdam UMC, location VUmc, Amsterdam, The Netherlands
- Cancer Center Amsterdam, Amsterdam UMC, Amsterdam, The Netherlands
| | - A F Engelsman
- Department of Surgery, Amsterdam UMC, location VUmc, Amsterdam, The Netherlands
- Cancer Center Amsterdam, Amsterdam UMC, Amsterdam, The Netherlands
| | - P van der Valk
- Department of Pathology, Amsterdam UMC, location VUmc, Amsterdam, The Netherlands
| | - M L Groot
- Vrije Universiteit Amsterdam, Faculty of Science, Department of Physics, LaserLab, Amsterdam, The Netherlands
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3
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van Huizen LMG, Blokker M, Rip Y, Veta M, Mooij Kalverda KA, Bonta PI, Duitman JW, Groot ML. Leukocyte differentiation in bronchoalveolar lavage fluids using higher harmonic generation microscopy and deep learning. PLoS One 2023; 18:e0279525. [PMID: 37368904 DOI: 10.1371/journal.pone.0279525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 06/11/2023] [Indexed: 06/29/2023] Open
Abstract
BACKGROUND In diseases such as interstitial lung diseases (ILDs), patient diagnosis relies on diagnostic analysis of bronchoalveolar lavage fluid (BALF) and biopsies. Immunological BALF analysis includes differentiation of leukocytes by standard cytological techniques that are labor-intensive and time-consuming. Studies have shown promising leukocyte identification performance on blood fractions, using third harmonic generation (THG) and multiphoton excited autofluorescence (MPEF) microscopy. OBJECTIVE To extend leukocyte differentiation to BALF samples using THG/MPEF microscopy, and to show the potential of a trained deep learning algorithm for automated leukocyte identification and quantification. METHODS Leukocytes from blood obtained from three healthy individuals and one asthma patient, and BALF samples from six ILD patients were isolated and imaged using label-free microscopy. The cytological characteristics of leukocytes, including neutrophils, eosinophils, lymphocytes, and macrophages, in terms of cellular and nuclear morphology, and THG and MPEF signal intensity, were determined. A deep learning model was trained on 2D images and used to estimate the leukocyte ratios at the image-level using the differential cell counts obtained using standard cytological techniques as reference. RESULTS Different leukocyte populations were identified in BALF samples using label-free microscopy, showing distinctive cytological characteristics. Based on the THG/MPEF images, the deep learning network has learned to identify individual cells and was able to provide a reasonable estimate of the leukocyte percentage, reaching >90% accuracy on BALF samples in the hold-out testing set. CONCLUSIONS Label-free THG/MPEF microscopy in combination with deep learning is a promising technique for instant differentiation and quantification of leukocytes. Immediate feedback on leukocyte ratios has potential to speed-up the diagnostic process and to reduce costs, workload and inter-observer variations.
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Affiliation(s)
- Laura M G van Huizen
- LaserLab Amsterdam, Department of Physics, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Max Blokker
- LaserLab Amsterdam, Department of Physics, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Yael Rip
- LaserLab Amsterdam, Department of Physics, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Mitko Veta
- Medical Image Analysis Group (IMAG/e), Department of Biomedical Engineering, University of Technology, Eindhoven, The Netherlands
| | - Kirsten A Mooij Kalverda
- Department of Pulmonary Medicine, Amsterdam UMC Location University of Amsterdam, Amsterdam, The Netherlands
| | - Peter I Bonta
- Department of Pulmonary Medicine, Amsterdam UMC Location University of Amsterdam, Amsterdam, The Netherlands
| | - Jan Willem Duitman
- Department of Pulmonary Medicine, Amsterdam UMC Location University of Amsterdam, Amsterdam, The Netherlands
- Department of Experimental immunology, Amsterdam UMC Location University of Amsterdam, Amsterdam, The Netherlands
- Amsterdam Infection & Immunity, Inflammatory Diseases, Amsterdam, The Netherlands
| | - Marie Louise Groot
- LaserLab Amsterdam, Department of Physics, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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4
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van Haasterecht L, Zhou M, Ma Y, Bartolini L, Van Mourik F, Van Zuijlen PPM, Groot ML. Visualizing dynamic three-dimensional changes of human reticular dermal collagen under mechanical strain. Biomed Phys Eng Express 2023; 9:035033. [PMID: 37054703 DOI: 10.1088/2057-1976/accc8e] [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: 11/29/2022] [Accepted: 04/13/2023] [Indexed: 04/15/2023]
Abstract
In clinical practice, plastic surgeons are often faced with large skin defects that are difficult to close primarily. Management of large skin wounds e.g. burns or traumatic lacerations requires knowledge of skin biomechanic properties. Research into skin microstructural adaptation to mechanical deformation has only been performed using static regimes due to technical limitations. Here, we combine uniaxial stretch tests with fast second harmonic generation imaging and we apply this for the first time to investigate dynamic collagen rearrangement in reticular human dermis.Ex vivohuman skin from the abdomen and upper thigh was simultaneously uniaxially stretched while either periodically visualizing 3D reorganization, or visualizing 2D changes in real time. We determined collagen alignment via orientation indices and found pronounced variability across samples. Comparing mean orientation indices at the different stages of the stress strain curves (toe, heel, linear) showed a significant increase in collagen alignment during the linear part of the mechanical response. We conclude that fast SHG imaging during uni-axial extension is a promising research tool for future studies on skin biomechanic properties.
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Affiliation(s)
- L van Haasterecht
- LaserLab Amsterdam, Department of Physics and Astronomy, Faculty of Sciences Vrije Universiteit, Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
- Amsterdam UMC, Vrije Universiteit, Department of Plastic, Reconstructive and Hand Surgery, Amsterdam Movement Sciences, PO Box 7057, 1007 MB Amsterdam, The Netherlands
- Burn Center, Red Cross Hospital, PO Box 1074, 1940 EB Beverwijk, The Netherlands
| | - M Zhou
- LaserLab Amsterdam, Department of Physics and Astronomy, Faculty of Sciences Vrije Universiteit, Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Y Ma
- LaserLab Amsterdam, Department of Physics and Astronomy, Faculty of Sciences Vrije Universiteit, Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - L Bartolini
- LaserLab Amsterdam, Department of Physics and Astronomy, Faculty of Sciences Vrije Universiteit, Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - F Van Mourik
- LaserLab Amsterdam, Department of Physics and Astronomy, Faculty of Sciences Vrije Universiteit, Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - P P M Van Zuijlen
- Amsterdam UMC, Vrije Universiteit, Department of Plastic, Reconstructive and Hand Surgery, Amsterdam Movement Sciences, PO Box 7057, 1007 MB Amsterdam, The Netherlands
- Burn Center, Red Cross Hospital, PO Box 1074, 1940 EB Beverwijk, The Netherlands
| | - M L Groot
- LaserLab Amsterdam, Department of Physics and Astronomy, Faculty of Sciences Vrije Universiteit, Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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5
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van Huizen LMG, Kalverda KA, Bugiani M, Poletti V, Bonta PI, Annema JT, Groot ML. Rapid On-Site Pathology Visualization of COVID-19 Characteristics Using Higher Harmonic Generation Microscopy. Am J Respir Crit Care Med 2023. [PMID: 36883981 PMCID: PMC10395503 DOI: 10.1164/rccm.202207-1259im] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023] Open
Affiliation(s)
- Laura M G van Huizen
- Vrije Universiteit Amsterdam, 1190, Dept. of Physics, LaserLab Amsterdam, Amsterdam, Netherlands;
| | - Kirsten A Kalverda
- Amsterdam UMC Locatie AMC, 26066, Pulmonology, Amsterdam, North Holland, Netherlands
| | - Marianna Bugiani
- Amsterdam UMC Locatie VUmc, 1209, Pathology, Amsterdam, Noord-Holland, Netherlands
| | - Venerino Poletti
- GB MORGAGNI HOSPITAL, INTERVENTIONAL PNEUMOLOGY, FORLì, FC, Italy
| | - Peter I Bonta
- Amsterdam UMC, 522567, Department of Pulmonology, Amsterdam, Noord-Holland, Netherlands
| | - Jouke T Annema
- Amsterdam UMC Location AMC, 26066, Pulmonology, Amsterdam, North Holland, Netherlands
| | - Marie Louise Groot
- Vrije Universiteit Amsterdam, 1190, Dept. of Physics, LaserLab Amsterdam, Amsterdam, Noord-Holland, Netherlands
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6
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Blokker M, Hamer PCDW, Wesseling P, Groot ML, Veta M. Fast intraoperative histology-based diagnosis of gliomas with third harmonic generation microscopy and deep learning. Sci Rep 2022; 12:11334. [PMID: 35790792 PMCID: PMC9256596 DOI: 10.1038/s41598-022-15423-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 06/23/2022] [Indexed: 11/09/2022] Open
Abstract
Management of gliomas requires an invasive treatment strategy, including extensive surgical resection. The objective of the neurosurgeon is to maximize tumor removal while preserving healthy brain tissue. However, the lack of a clear tumor boundary hampers the neurosurgeon's ability to accurately detect and resect infiltrating tumor tissue. Nonlinear multiphoton microscopy, in particular higher harmonic generation, enables label-free imaging of excised brain tissue, revealing histological hallmarks within seconds. Here, we demonstrate a real-time deep learning-based pipeline for automated glioma image analysis, matching video-rate image acquisition. We used a custom noise detection scheme, and a fully-convolutional classification network, to achieve on average 79% binary accuracy, 0.77 AUC and 0.83 mean average precision compared to the consensus of three pathologists, on a preliminary dataset. We conclude that the combination of real-time imaging and image analysis shows great potential for intraoperative assessment of brain tissue during tumor surgery.
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Affiliation(s)
- Max Blokker
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
| | - Philip C de Witt Hamer
- Department of Neurosurgery, Amsterdam UMC location VU University Medical Center, Amsterdam, The Netherlands
| | - Pieter Wesseling
- Department of Pathology, Amsterdam UMC location VU University Medical Center, Amsterdam, The Netherlands
| | - Marie Louise Groot
- Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Mitko Veta
- Medical Image Analysis Group (IMAG/e), Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
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7
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Raktoe RS, van Haasterecht L, Antonovaite N, Bartolini L, van Doorn R, van Zuijlen PPM, Groot ML, El Ghalbzouri A. The effect of TGFβRI inhibition on extracellular matrix structure and stiffness in hypertrophic scar-specific fibroblast-derived matrix models. Biochem Biophys Res Commun 2021; 559:245-251. [PMID: 33964734 DOI: 10.1016/j.bbrc.2021.04.071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 04/17/2021] [Indexed: 11/16/2022]
Affiliation(s)
- Rajiv S Raktoe
- Department of Dermatology, Leiden University Medical Centre, 2333 ZA, Leiden, the Netherlands.
| | - Ludo van Haasterecht
- LaserLaB Amsterdam, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, the Netherlands; Burn Center and Department of Plastic and Reconstructive Surgery, Red Cross Hospital, P.O. Box 1074, 1940 EB, Beverwijk, the Netherlands; Amsterdam UMC Location VUmc, Department of Plastic, Reconstructive and Hand Surgery, Amsterdam Movement Sciences, PO Box 7057, 1007 MB, Amsterdam, the Netherlands
| | - Nelda Antonovaite
- LaserLaB Amsterdam, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, the Netherlands
| | - Luca Bartolini
- LaserLaB Amsterdam, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, the Netherlands
| | - Remco van Doorn
- Department of Dermatology, Leiden University Medical Centre, 2333 ZA, Leiden, the Netherlands
| | - Paul P M van Zuijlen
- Burn Center and Department of Plastic and Reconstructive Surgery, Red Cross Hospital, P.O. Box 1074, 1940 EB, Beverwijk, the Netherlands; Amsterdam UMC Location VUmc, Department of Plastic, Reconstructive and Hand Surgery, Amsterdam Movement Sciences, PO Box 7057, 1007 MB, Amsterdam, the Netherlands
| | - Marie Louise Groot
- LaserLaB Amsterdam, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, the Netherlands
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8
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van Huizen LMG, Radonic T, van Mourik F, Seinstra D, Dickhoff C, Daniels JMA, Bahce I, Annema JT, Groot ML. Compact portable multiphoton microscopy reveals histopathological hallmarks of unprocessed lung tumor tissue in real time. Transl Biophotonics 2020; 2:e202000009. [PMID: 34341777 PMCID: PMC8311669 DOI: 10.1002/tbio.202000009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/18/2020] [Accepted: 07/06/2020] [Indexed: 12/11/2022] Open
Abstract
During lung cancer operations a rapid and reliable assessment of tumor tissue can reduce operation time and potentially improve patient outcomes. We show that third harmonic generation (THG), second harmonic generation (SHG) and two-photon excited autofluorescence (2PEF) microscopy reveals relevant, histopathological information within seconds in fresh unprocessed human lung samples. We used a compact, portable microscope and recorded images within 1 to 3 seconds using a power of 5 mW. The generated THG/SHG/2PEF images of tumorous and nontumorous tissues are compared with the corresponding standard histology images, to identify alveolar structures and histopathological hallmarks. Cellular structures (tumor cells, macrophages and lymphocytes) (THG), collagen (SHG) and elastin (2PEF) are differentiated and allowed for rapid identification of carcinoid with solid growth pattern, minimally enlarged monomorphic cell nuclei with salt-and-pepper chromatin pattern, and adenocarcinoma with lipidic and micropapillary growth patterns. THG/SHG/2PEF imaging is thus a promising tool for clinical intraoperative assessment of lung tumor tissue.
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Affiliation(s)
- Laura M. G. van Huizen
- Faculty of Science, Department of Physics, LaserLabVrije Universiteit AmsterdamAmsterdamNetherlands
| | - Teodora Radonic
- Department of PathologyAmsterdam Universities Medical Center/VU University Medical CenterAmsterdamNetherlands
| | | | - Danielle Seinstra
- Department of PathologyAmsterdam Universities Medical Center/VU University Medical CenterAmsterdamNetherlands
| | - Chris Dickhoff
- Department of SurgeryAmsterdam Universities Medical CenterAmsterdamNetherlands
| | - Johannes M. A. Daniels
- Department of Pulmonary DiseasesAmsterdam Universities Medical CenterAmsterdamNetherlands
| | - Idris Bahce
- Department of Pulmonary DiseasesAmsterdam Universities Medical CenterAmsterdamNetherlands
| | - Jouke T. Annema
- Department of Pulmonary DiseasesAmsterdam Universities Medical CenterAmsterdamNetherlands
| | - Marie Louise Groot
- Faculty of Science, Department of Physics, LaserLabVrije Universiteit AmsterdamAmsterdamNetherlands
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9
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Konold PE, Arik E, Weißenborn J, Arents JC, Hellingwerf KJ, van Stokkum IHM, Kennis JTM, Groot ML. Confinement in crystal lattice alters entire photocycle pathway of the Photoactive Yellow Protein. Nat Commun 2020; 11:4248. [PMID: 32843623 PMCID: PMC7447820 DOI: 10.1038/s41467-020-18065-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 07/31/2020] [Indexed: 11/27/2022] Open
Abstract
Femtosecond time-resolved crystallography (TRC) on proteins enables resolving the spatial structure of short-lived photocycle intermediates. An open question is whether confinement and lower hydration of the proteins in the crystalline state affect the light-induced structural transformations. Here, we measured the full photocycle dynamics of a signal transduction protein often used as model system in TRC, Photoactive Yellow Protein (PYP), in the crystalline state and compared those to the dynamics in solution, utilizing electronic and vibrational transient absorption measurements from 100 fs over 12 decades in time. We find that the photocycle kinetics and structural dynamics of PYP in the crystalline form deviate from those in solution from the very first steps following photon absorption. This illustrates that ultrafast TRC results cannot be uncritically extrapolated to in vivo function, and that comparative spectroscopic experiments on proteins in crystalline and solution states can help identify structural intermediates under native conditions. Protein structural dynamics can be studied by time-resolved crystallography (TRC) and ultrafast transient spectroscopic methods. Here, the authors perform electronic and vibrational transient absorption measurements to characterise the full photocycle of Photoactive Yellow Protein (PYP) both in the crystalline and solution state and find that the photocycle kinetics and structural intermediates of PYP deviate in the crystalline state, which must be taken into consideration when planning TRC experiments.
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Affiliation(s)
- Patrick E Konold
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Enis Arik
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Jörn Weißenborn
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Jos C Arents
- Laboratory for Microbiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park, 1098, XH, Amsterdam, The Netherlands
| | - Klaas J Hellingwerf
- Laboratory for Microbiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park, 1098, XH, Amsterdam, The Netherlands
| | - Ivo H M van Stokkum
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - John T M Kennis
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Marie Louise Groot
- Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands.
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10
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Kwa KAA, van Haasterecht L, Elgersma A, Breederveld RS, Groot ML, van Zuijlen PPM, Boekema BKHL. Effective enzymatic debridement of burn wounds depends on the denaturation status of collagen. Wound Repair Regen 2020; 28:666-675. [PMID: 32570295 DOI: 10.1111/wrr.12827] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 04/30/2020] [Accepted: 05/05/2020] [Indexed: 12/21/2022]
Abstract
The treatment of burn wounds by enzymatic debridement using bromelain has shown promising results in our burn center. However, inadequate debridement occurred in a few cases in which the etiology of the burn was attributed to relatively low temperature burns. We hypothesized that bromelain is ineffective in burns in which collagen denaturation, which occurs approximately at 65°C, has not taken place. Our objective was to assess whether there is a relationship between the denaturation of collagen and the ability of bromelain to debride acute scald burn wounds of different temperatures. Ex vivo human skin from four different donors was cut into 1x1 cm samples, and scald burns were produced by immersion in water at temperatures of 40°C, 50°C, 60°C, 70°C, and 100°C for 20 minutes. Denaturation of collagen was assessed with histology, using hematoxylin and eosin (H&E) staining and a fluorescently labeled collagen hybridizing peptide (CHP), and with second harmonic generation (SHG) microscopy. Burned samples and one control sample (room temperature) were weighed before and after application of enzymatic debridement to assess the efficacy of enzymatic debridement. After enzymatic debridement, a weight reduction of 80% was seen in the samples heated to 70°C and 100°C, whereas the other samples showed a reduction of 20%. Unfolding of collagen, loss of basket-weave arrangement, and necrosis was seen in samples heated to 60°C or higher. Evident CHP fluorescence, indicative of collagen denaturation, was seen in samples of 60°C, 70°C and 100°C. SHG intensity, signifying intact collagen, was significantly lower in the 70°C and 100°C group (P <.05) compared to the lower temperatures. In conclusion, denaturation of collagen in skin samples occurred between 60°C and 70°C and strongly correlated with the efficacy of enzymatic debridement. Therefore, enzymatic debridement with the use of bromelain is ineffective in scald burns lower than 60°C.
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Affiliation(s)
- Kelly A A Kwa
- Burn Center, Red Cross Hospital, Beverwijk, The Netherlands.,Department of Traumasurgery, Leiden University Medical Center, Leiden, The Netherlands
| | - Ludo van Haasterecht
- LaserLaB Amsterdam, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.,Amsterdam UMC Location VUmc, Department of Plastic, Reconstructive and Hand Surgery, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Anouk Elgersma
- Preclinical Research, Association of Dutch Burn Centers, Beverwijk, The Netherlands
| | - Roelf S Breederveld
- Burn Center, Red Cross Hospital, Beverwijk, The Netherlands.,Department of Traumasurgery, Leiden University Medical Center, Leiden, The Netherlands
| | - Marie Louise Groot
- LaserLaB Amsterdam, Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Paul P M van Zuijlen
- Burn Center, Red Cross Hospital, Beverwijk, The Netherlands.,Amsterdam UMC Location VUmc, Department of Plastic, Reconstructive and Hand Surgery, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Bouke K H L Boekema
- Preclinical Research, Association of Dutch Burn Centers, Beverwijk, The Netherlands
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11
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van Haasterecht L, Zada L, Schmidt RW, de Bakker E, Barbé E, Leslie HA, Vethaak AD, Gibbs S, de Boer JF, Niessen FB, van Zuijlen PPM, Groot ML, Ariese F. Label-free stimulated Raman scattering imaging reveals silicone breast implant material in tissue. J Biophotonics 2020; 13:e201960197. [PMID: 32049417 DOI: 10.1002/jbio.201960197] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 02/05/2020] [Accepted: 02/07/2020] [Indexed: 06/10/2023]
Abstract
Millions of women worldwide have silicone breast implants. It has been reported that implant failure occurs in approximately a tenth of patients within 10 years, and the consequences of dissemination of silicone debris are poorly understood. Currently, silicone detection in histopathological slides is based on morphological features as no specific immunohistochemical technique is available. Here, we show the feasibility and sensitivity of stimulated Raman scattering (SRS) imaging to specifically detect silicone material in stained histopathological slides, without additional sample treatment. Histology slides of four periprosthetic capsules from different implant types were obtained after explantation, as well as an enlarged axillary lymph node from a patient with a ruptured implant. SRS images coregistered with bright-field images revealed the distribution and quantity of silicone material in the tissue. Fast and high-resolution imaging of histology slides with molecular specificity using SRS provides an opportunity to investigate the role of silicone debris in the pathophysiology of implant-linked diseases.
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Affiliation(s)
- Ludo van Haasterecht
- LaserLaB Amsterdam, Department of Physics and Astronomy, Faculty of Sciences Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Department of Plastic, Reconstructive and Hand Surgery, Amsterdam UMC Location VUMC, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Liron Zada
- LaserLaB Amsterdam, Department of Physics and Astronomy, Faculty of Sciences Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Department of Environment and Health, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Robert W Schmidt
- LaserLaB Amsterdam, Department of Physics and Astronomy, Faculty of Sciences Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Erik de Bakker
- Department of Plastic, Reconstructive and Hand Surgery, Amsterdam UMC Location VUMC, Amsterdam Movement Sciences, Amsterdam, The Netherlands
- Department of Molecular Cell Biology and Immunology, Amsterdam UMC Location VUMC, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Ellis Barbé
- Department of Pathology, Amsterdam UMC Location VUMC, Amsterdam, The Netherlands
| | - Heather A Leslie
- Department of Environment and Health, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - A Dick Vethaak
- Department of Environment and Health, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
- Deltares, Marine and Coastal Systems, Delft, The Netherlands
| | - Susan Gibbs
- Department of Molecular Cell Biology and Immunology, Amsterdam UMC Location VUMC, Amsterdam Movement Sciences, Amsterdam, The Netherlands
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Johannes F de Boer
- LaserLaB Amsterdam, Department of Physics and Astronomy, Faculty of Sciences Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Frank B Niessen
- Department of Plastic, Reconstructive and Hand Surgery, Amsterdam UMC Location VUMC, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Paul P M van Zuijlen
- Department of Plastic, Reconstructive and Hand Surgery, Amsterdam UMC Location VUMC, Amsterdam Movement Sciences, Amsterdam, The Netherlands
- Burn Center and Department of Plastic and Reconstructive Surgery, Red Cross Hospital, Beverwijk, The Netherlands
| | - Marie Louise Groot
- LaserLaB Amsterdam, Department of Physics and Astronomy, Faculty of Sciences Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Freek Ariese
- LaserLaB Amsterdam, Department of Physics and Astronomy, Faculty of Sciences Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
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12
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Zhang Z, de Munck JC, Verburg N, Rozemuller AJ, Vreuls W, Cakmak P, van Huizen LMG, Idema S, Aronica E, de Witt Hamer PC, Wesseling P, Groot ML. Quantitative Third Harmonic Generation Microscopy for Assessment of Glioma in Human Brain Tissue. Adv Sci (Weinh) 2019; 6:1900163. [PMID: 31179222 PMCID: PMC6548968 DOI: 10.1002/advs.201900163] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 02/20/2019] [Indexed: 06/02/2023]
Abstract
Distinguishing tumors from normal brain cells is important but challenging in glioma surgery due to the lack of clear interfaces between the two. The ability of label-free third harmonic generation (THG) microscopy in combination with automated image analysis to quantitatively detect glioma infiltration in fresh, unprocessed tissue in real time is assessed. The THG images reveal increased cellularity in grades II-IV glioma samples from 23 patients, as confirmed by subsequent hematoxylin and eosin histology. An automated image quantification workflow is presented for quantitative assessment of the imaged cellularity as a reflection of the degree of glioma invasion. The cellularity is validated in three ways: 1) Quantitative comparison of THG imaging with fluorescence microscopy of nucleus-stained samples demonstrates that THG reflects the true tissue cellularity. 2) Thresholding of THG cellularity differentiates normal brain from glioma infiltration, with 96.6% sensitivity and 95.5% specificity, in nearly perfect (93%) agreement with pathologists. 3) In one patient, a good correlation between THG cellularity and preoperative magnetic resonance and positron emission tomography imaging is demonstrated. In conclusion, quantitative real-time THG microscopy accurately assesses glioma infiltration in ex vivo human brain samples, and therefore holds strong potential for improving the accuracy of surgical resection.
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Affiliation(s)
- Zhiqing Zhang
- LaserLab AmsterdamDepartment of Physics and AstronomyFaculty of SciencesVrije Universiteit AmsterdamDe Boelelaan 10811081HVAmsterdamThe Netherlands
- Department of Radiology and Nuclear MedicineAmsterdam Universities Medical Center/VU University Medical CenterDe Boelelaan 11181081HZAmsterdamThe Netherlands
- Amsterdam NeuroscienceVrije Universiteit AmsterdamDe Boelelaan 10851081HVAmsterdamThe Netherlands
| | - Jan C. de Munck
- Department of Radiology and Nuclear MedicineAmsterdam Universities Medical Center/VU University Medical CenterDe Boelelaan 11181081HZAmsterdamThe Netherlands
| | - Niels Verburg
- Amsterdam Brain Tumor CenterAmsterdam Universities Medical Center/VU University Medical CenterDe Boelelaan 11171081HVAmsterdamThe Netherlands
- Department of NeurosurgeryAmsterdam Universities Medical Center/VU University Medical CenterDe Boelelaan 11171081HVAmsterdamThe Netherlands
| | - Annemieke J. Rozemuller
- Department of PathologyAmsterdam Universities Medical Center/VU University Medical CenterDe Boelelaan 11171081HVAmsterdamThe Netherlands
| | - Willem Vreuls
- Department of PathologyCanisius Wilhelmina ZiekenhuisWeg door jonkerbos 100, Postbus 90156500GSNijmegenThe Netherlands
| | - Pinar Cakmak
- Department of PathologyGazi University Medical FacultyBesevler06500AnkaraTurkey
| | - Laura M. G. van Huizen
- LaserLab AmsterdamDepartment of Physics and AstronomyFaculty of SciencesVrije Universiteit AmsterdamDe Boelelaan 10811081HVAmsterdamThe Netherlands
| | - Sander Idema
- Department of NeurosurgeryAmsterdam Universities Medical Center/VU University Medical CenterDe Boelelaan 11171081HVAmsterdamThe Netherlands
| | - Eleonora Aronica
- Department of (Neuro) PathologyAmsterdam UMCUniversity of AmsterdamMeibergdreef 91105AZAmsterdamThe Netherlands
| | - Philip C. de Witt Hamer
- Amsterdam Brain Tumor CenterAmsterdam Universities Medical Center/VU University Medical CenterDe Boelelaan 11171081HVAmsterdamThe Netherlands
- Department of NeurosurgeryAmsterdam Universities Medical Center/VU University Medical CenterDe Boelelaan 11171081HVAmsterdamThe Netherlands
| | - Pieter Wesseling
- Amsterdam Brain Tumor CenterAmsterdam Universities Medical Center/VU University Medical CenterDe Boelelaan 11171081HVAmsterdamThe Netherlands
- Department of PathologyAmsterdam Universities Medical Center/VU University Medical CenterDe Boelelaan 11171081HVAmsterdamThe Netherlands
- Princess Máxima Center for Pediatric Oncology and Department of PathologyUniversity Medical Center UtrechtHeidelberglaan 253584CSUtrechtThe Netherlands
| | - Marie Louise Groot
- LaserLab AmsterdamDepartment of Physics and AstronomyFaculty of SciencesVrije Universiteit AmsterdamDe Boelelaan 10811081HVAmsterdamThe Netherlands
- Amsterdam NeuroscienceVrije Universiteit AmsterdamDe Boelelaan 10851081HVAmsterdamThe Netherlands
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13
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van Huizen LM, Kuzmin NV, Barbé E, van der Velde S, te Velde EA, Groot ML. Second and third harmonic generation microscopy visualizes key structural components in fresh unprocessed healthy human breast tissue. J Biophotonics 2019; 12:e201800297. [PMID: 30684312 PMCID: PMC7065644 DOI: 10.1002/jbio.201800297] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 01/22/2019] [Accepted: 01/24/2019] [Indexed: 05/04/2023]
Abstract
Real-time assessment of excised tissue may help to improve surgical results in breast tumor surgeries. Here, as a step towards this purpose, the potential of second and third harmonic generation (SHG, THG) microscopy is explored. SHG and THG are nonlinear optical microscopic techniques that do not require labeling of tissue to generate 3D images with intrinsic depth-sectioning at sub-cellular resolution. Until now, this technique had been applied on fixated breast tissue or to visualize the stroma only, whereas most tumors start in the lobules and ducts. Here, SHG/THG images of freshly excised unprocessed healthy human tissue are shown to reveal key breast components-lobules, ducts, fat tissue, connective tissue and blood vessels, in good agreement with hematoxylin and eosin histology. DNA staining of fresh unprocessed mouse breast tissue was performed to aid in the identification of cell nuclei in label-free THG images. Furthermore, 2- and 3-photon excited auto-fluorescence images of mouse and human tissue are collected for comparison. The SHG/THG imaging modalities generate high quality images of freshly excised tissue in less than a minute with an information content comparable to that of the gold standard, histopathology. Therefore, SHG/THG microscopy is a promising tool for real-time assessment of excised tissue during surgery.
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Affiliation(s)
- Laura M.G. van Huizen
- Department of PhysicsLaserLab, Faculty of Science, VU AmsterdamAmsterdamThe Netherlands
| | - Nikolay V. Kuzmin
- Department of PhysicsLaserLab, Faculty of Science, VU AmsterdamAmsterdamThe Netherlands
| | - Ellis Barbé
- Department of PathologyAmsterdam UMC/VU University Medical CenterAmsterdamThe Netherlands
| | - Susanne van der Velde
- Department of SurgeryAmsterdam UMC/VU University Medical CenterAmsterdamThe Netherlands
| | - Elisabeth A. te Velde
- Department of SurgeryAmsterdam UMC/VU University Medical CenterAmsterdamThe Netherlands
| | - Marie Louise Groot
- Department of PhysicsLaserLab, Faculty of Science, VU AmsterdamAmsterdamThe Netherlands
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14
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Zhang Z, Kuzmin NV, Groot ML, de Munck JC. Extracting morphologies from third harmonic generation images of structurally normal human brain tissue. Bioinformatics 2018; 33:1712-1720. [PMID: 28130231 DOI: 10.1093/bioinformatics/btx035] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 01/19/2017] [Indexed: 11/14/2022] Open
Abstract
Motivation The morphologies contained in 3D third harmonic generation (THG) images of human brain tissue can report on the pathological state of the tissue. However, the complexity of THG brain images makes the usage of modern image processing tools, especially those of image filtering, segmentation and validation, to extract this information challenging. Results We developed a salient edge-enhancing model of anisotropic diffusion for image filtering, based on higher order statistics. We split the intrinsic 3-phase segmentation problem into two 2-phase segmentation problems, each of which we solved with a dedicated model, active contour weighted by prior extreme. We applied the novel proposed algorithms to THG images of structurally normal ex-vivo human brain tissue, revealing key tissue components-brain cells, microvessels and neuropil, enabling statistical characterization of these components. Comprehensive comparison to manually delineated ground truth validated the proposed algorithms. Quantitative comparison to second harmonic generation/auto-fluorescence images, acquired simultaneously from the same tissue area, confirmed the correctness of the main THG features detected. Availability and Implementation The software and test datasets are available from the authors. Contact z.zhang@vu.nl. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Zhiqing Zhang
- LaserLab Amsterdam, Department of Physics, Faculty of Sciences, VU University, HV Amsterdam, The Netherlands.,Physics and Medical Technology Department, VU University Medical Center, HZ Amsterdam, The Netherlands
| | - Nikolay V Kuzmin
- LaserLab Amsterdam, Department of Physics, Faculty of Sciences, VU University, HV Amsterdam, The Netherlands.,Neuroscience Campus Amsterdam, VU University, HV Amsterdam, The Netherlands
| | - Marie Louise Groot
- LaserLab Amsterdam, Department of Physics, Faculty of Sciences, VU University, HV Amsterdam, The Netherlands.,Neuroscience Campus Amsterdam, VU University, HV Amsterdam, The Netherlands
| | - Jan C de Munck
- Physics and Medical Technology Department, VU University Medical Center, ?HZ Amsterdam, The Netherlands
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15
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Zhang Z, Kuzmin NV, Groot ML, de Munck JC. Quantitative comparison of 3D third harmonic generation and fluorescence microscopy images. J Biophotonics 2018; 11:e201600256. [PMID: 28464543 DOI: 10.1002/jbio.201600256] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 12/22/2016] [Accepted: 01/23/2017] [Indexed: 06/07/2023]
Abstract
Third harmonic generation (THG) microscopy is a label-free imaging technique that shows great potential for rapid pathology of brain tissue during brain tumor surgery. However, the interpretation of THG brain images should be quantitatively linked to images of more standard imaging techniques, which so far has been done qualitatively only. We establish here such a quantitative link between THG images of mouse brain tissue and all-nuclei-highlighted fluorescence images, acquired simultaneously from the same tissue area. For quantitative comparison of a substantial pair of images, we present here a segmentation workflow that is applicable for both THG and fluorescence images, with a precision of 91.3 % and 95.8 % achieved respectively. We find that the correspondence between the main features of the two imaging modalities amounts to 88.9 %, providing quantitative evidence of the interpretation of dark holes as brain cells. Moreover, 80 % bright objects in THG images overlap with nuclei highlighted in the fluorescence images, and they are 2 times smaller than the dark holes, showing that cells of different morphologies can be recognized in THG images. We expect that the described quantitative comparison is applicable to other types of brain tissue and with more specific staining experiments for cell type identification.
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Affiliation(s)
- Zhiqing Zhang
- LaserLab Amsterdam, Department of Physics, Faculty of Sciences, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
- Physics and Medical Technology department, VU University Medical Center, De Boelelaan 1118, 1081 HZ Amsterdam, The Netherlands
| | - Nikolay V Kuzmin
- LaserLab Amsterdam, Department of Physics, Faculty of Sciences, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
- Neuroscience Campus Amsterdam, VU University, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
| | - Marie Louise Groot
- LaserLab Amsterdam, Department of Physics, Faculty of Sciences, VU University, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
- Neuroscience Campus Amsterdam, VU University, De Boelelaan 1085, 1081 HV, Amsterdam, The Netherlands
| | - Jan C de Munck
- Physics and Medical Technology department, VU University Medical Center, De Boelelaan 1118, 1081 HZ Amsterdam, The Netherlands
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16
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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: 44] [Impact Index Per Article: 5.5] [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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17
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Visscher DO, Bos EJ, Peeters M, Kuzmin NV, Groot ML, Helder MN, van Zuijlen PPM. Cartilage Tissue Engineering: Preventing Tissue Scaffold Contraction Using a 3D-Printed Polymeric Cage. Tissue Eng Part C Methods 2016; 22:573-84. [PMID: 27089896 DOI: 10.1089/ten.tec.2016.0073] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [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: 01/19/2023] Open
Abstract
Scaffold contraction is a common but underestimated problem in the field of tissue engineering. It becomes particularly problematic when creating anatomically complex shapes such as the ear. The aim of this study was to develop a contraction-free biocompatible scaffold construct for ear cartilage tissue engineering. To address this aim, we used three constructs: (i) a fibrin/hyaluronic acid (FB/HA) hydrogel, (ii) a FB/HA hydrogel combined with a collagen I/III scaffold, and (iii) a cage construct containing (ii) surrounded by a 3D-printed poly-ɛ-caprolactone mold. A wide range of different cell types were tested within these constructs, including chondrocytes, perichondrocytes, adipose-derived mesenchymal stem cells, and their combinations. After in vitro culturing for 1, 14, and 28 days, all constructs were analyzed. Macroscopic observation showed severe contraction of the cell-seeded hydrogel (i). This could be prevented, in part, by combining the hydrogel with the collagen scaffold (ii) and prevented in total using the 3D-printed cage construct (iii). (Immuno)histological analysis, multiphoton laser scanning microscopy, and biomechanical analysis showed extracellular matrix deposition and increased Young's modulus and thereby the feasibility of ear cartilage engineering. These results demonstrated that the 3D-printed cage construct is an adequate model for contraction-free ear cartilage engineering using a range of cell combinations.
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Affiliation(s)
- Dafydd O Visscher
- 1 Department of Plastic, Reconstructive & Hand Surgery, VU Medical Center , Amsterdam, Netherlands
- 2 CTRM/MOVE Research Institute , Amsterdam, Netherlands
| | - Ernst J Bos
- 1 Department of Plastic, Reconstructive & Hand Surgery, VU Medical Center , Amsterdam, Netherlands
- 2 CTRM/MOVE Research Institute , Amsterdam, Netherlands
| | - Mirte Peeters
- 2 CTRM/MOVE Research Institute , Amsterdam, Netherlands
- 3 Department of Orthopedic Surgery, VU Medical Center , Amsterdam, Netherlands
| | - Nikolay V Kuzmin
- 4 LaserLaB Amsterdam, Department of Physics, Vrije Universiteit , Amsterdam, Netherlands
| | - Marie Louise Groot
- 4 LaserLaB Amsterdam, Department of Physics, Vrije Universiteit , Amsterdam, Netherlands
| | - Marco N Helder
- 2 CTRM/MOVE Research Institute , Amsterdam, Netherlands
- 3 Department of Orthopedic Surgery, VU Medical Center , Amsterdam, Netherlands
| | - Paul P M van Zuijlen
- 1 Department of Plastic, Reconstructive & Hand Surgery, VU Medical Center , Amsterdam, Netherlands
- 2 CTRM/MOVE Research Institute , Amsterdam, Netherlands
- 5 Red Cross Hospital Beverwijk , Beverwijk, Netherlands
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18
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Zhu J, Vreede J, Hospes M, Arents J, Kennis JTM, van Stokkum IHM, Hellingwerf KJ, Groot ML. Short Hydrogen Bonds and Negative Charge in Photoactive Yellow Protein Promote Fast Isomerization but not High Quantum Yield. J Phys Chem B 2014; 119:2372-83. [DOI: 10.1021/jp506785q] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jingyi Zhu
- Department
of Physics and Astronomy, Faculty of Sciences, LaserLab, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | | | | | | | - John T. M. Kennis
- Department
of Physics and Astronomy, Faculty of Sciences, LaserLab, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Ivo H. M. van Stokkum
- Department
of Physics and Astronomy, Faculty of Sciences, LaserLab, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | | | - Marie Louise Groot
- Department
of Physics and Astronomy, Faculty of Sciences, LaserLab, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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19
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Zhu J, van Stokkum IHM, Paparelli L, Jones MR, Groot ML. Early bacteriopheophytin reduction in charge separation in reaction centers of Rhodobacter sphaeroides. Biophys J 2014; 104:2493-502. [PMID: 23746522 DOI: 10.1016/j.bpj.2013.04.026] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 04/11/2013] [Accepted: 04/12/2013] [Indexed: 11/16/2022] Open
Abstract
A question at the forefront of biophysical sciences is, to what extent do quantum effects and protein conformational changes play a role in processes such as biological sensing and energy conversion? At the heart of photosynthetic energy transduction lie processes involving ultrafast energy and electron transfers among a small number of tetrapyrrole pigments embedded in the interior of a protein. In the purple bacterial reaction center (RC), a highly efficient ultrafast charge separation takes place between a pair of bacteriochlorophylls: an accessory bacteriochlorophyll (B) and bacteriopheophytin (H). In this work, we applied ultrafast spectroscopy in the visible and near-infrared spectral region to Rhodobacter sphaeroides RCs to accurately track the timing of the electron on BA and HA via the appearance of the BA and HA anion bands. We observed an unexpectedly early rise of the HA⁻ band that challenges the accepted simple picture of stepwise electron transfer with 3 ps and 1 ps time constants. The implications for the mechanism of initial charge separation in bacterial RCs are discussed in terms of a possible adiabatic electron transfer step between BA and HA, and the effect of protein conformation on the electron transfer rate.
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Affiliation(s)
- Jingyi Zhu
- Department of Physics, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
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20
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Zhu J, Paparelli L, Hospes M, Arents J, Kennis JTM, van Stokkum IHM, Hellingwerf KJ, Groot ML. Correction to “Photoionization and Electron Radical Recombination Dynamics in Photoactive Yellow Protein Investigated by Ultrafast Spectroscopy in the Visible and Near-Infrared Spectral Region”. J Phys Chem B 2013. [DOI: 10.1021/jp409999w] [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: 11/28/2022]
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21
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Zhu J, Paparelli L, Hospes M, Arents J, Kennis JTM, van Stokkum IHM, Hellingwerf KJ, Groot ML. Photoionization and Electron Radical Recombination Dynamics in Photoactive Yellow Protein Investigated by Ultrafast Spectroscopy in the Visible and Near-Infrared Spectral Region. J Phys Chem B 2013; 117:11042-8. [DOI: 10.1021/jp311906f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jingyi Zhu
- Department
of Physics and Astronomy,
Faculty of Sciences, VU University, De
Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Laura Paparelli
- Department
of Physics and Astronomy,
Faculty of Sciences, VU University, De
Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Marijke Hospes
- Laboratory for Microbiology,
Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The
Netherlands
| | - Jos Arents
- Laboratory for Microbiology,
Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The
Netherlands
| | - John T. M. Kennis
- Department
of Physics and Astronomy,
Faculty of Sciences, VU University, De
Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Ivo H. M. van Stokkum
- Department
of Physics and Astronomy,
Faculty of Sciences, VU University, De
Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Klaas J. Hellingwerf
- Laboratory for Microbiology,
Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The
Netherlands
| | - Marie Louise Groot
- Department
of Physics and Astronomy,
Faculty of Sciences, VU University, De
Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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22
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Zhu J, Paparelli L, Hospes M, Arents J, Hellingwerf K, Kennis JT, van Stokkum IH, Louise Groot M. Ultrafast geminate electron-radical recombination dynamics in photoactive yellow protein. EPJ Web of Conferences 2013. [DOI: 10.1051/epjconf/20134107010] [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: 11/14/2022] Open
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23
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Witte S, Plauşka A, Ridder MC, van Berge L, Mansvelder HD, Groot ML. Short-coherence off-axis holographic phase microscopy of live cell dynamics. Biomed Opt Express 2012; 3:2184-9. [PMID: 23024912 PMCID: PMC3447560 DOI: 10.1364/boe.3.002184] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 08/22/2012] [Accepted: 08/22/2012] [Indexed: 05/07/2023]
Abstract
We demonstrate a single-shot holographic phase microscope that combines short-coherence laser pulses with an off-axis geometry. By introducing a controlled pulse front tilt, ultrashort pulses are made to interfere over a large field-of-view without loss of fringe contrast. With this microscope, quantitative phase images of live cells can be recorded in a full-field geometry without moving parts. We perform phase imaging of HEK293 cells, to study the dynamics of cell volume regulation in response to an osmotic shock.
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Affiliation(s)
- Stefan Witte
- These authors contributed equally to this work
- LaserLaB, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Andrius Plauşka
- These authors contributed equally to this work
- LaserLaB, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Margreet C. Ridder
- Department of Child Neurology, VU University Medical Centre, 1081 HV Amsterdam, The Netherlands
| | - Laura van Berge
- Department of Child Neurology, VU University Medical Centre, 1081 HV Amsterdam, The Netherlands
| | - Huibert D. Mansvelder
- Department of Integrative Neurophysiology, CNCR, VU University, Amsterdam, Netherlands
- Neuroscience Campus Amsterdam, VU University, 1081 HV Amsterdam, The Netherlands
| | - Marie Louise Groot
- LaserLaB, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
- Neuroscience Campus Amsterdam, VU University, 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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Scrutton NS, Louise Groot M, Heyes DJ. Excited state dynamics and catalytic mechanism of the light-driven enzyme protochlorophyllide oxidoreductase. Phys Chem Chem Phys 2012; 14:8818-24. [DOI: 10.1039/c2cp23789j] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Sytina OA, van Stokkum IHM, Heyes DJ, Hunter CN, Groot ML. Spectroscopic characterization of the first ultrafast catalytic intermediate in protochlorophyllide oxidoreductase. Phys Chem Chem Phys 2012; 14:616-25. [DOI: 10.1039/c1cp21713e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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27
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van Oort B, ter Veer MJT, Groot ML, van Stokkum IHM. Excited state proton transfer in strongly enhanced GFP (sGFP2). Phys Chem Chem Phys 2012; 14:8852-8. [DOI: 10.1039/c2cp40694b] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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28
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Stahl AD, Crouch LI, Jones MR, van Stokkum I, van Grondelle R, Groot ML. Role of PufX in Photochemical Charge Separation in the RC-LH1 Complex from Rhodobacter sphaeroides: An Ultrafast Mid-IR Pump–Probe Investigation. J Phys Chem B 2011; 116:434-44. [DOI: 10.1021/jp206697k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Andreas D. Stahl
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
| | - Lucy I. Crouch
- School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
| | - Michael R. Jones
- School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, United Kingdom
| | - Ivo van Stokkum
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
| | - Rienk van Grondelle
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
| | - Marie Louise Groot
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
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Sytina OA, Novoderezhkin VI, van Grondelle R, Groot ML. Modeling of multi-exciton transient absorption spectra of protochlorophyllide aggregates in aqueous solution. J Phys Chem A 2011; 115:11944-51. [PMID: 21936513 DOI: 10.1021/jp204395z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Protochlorophyllide (Pchlide) is a natural porphyrin, a precursor of chlorophyll, synthesized by plants for its photosynthetic apparatus. The pigment spontaneously forms aggregates when dissolved in neat water solution. We present here calculations of the transient absorption spectra and its comprising components (ground-state bleach, stimulated emission, and excited-state absorption) for a strongly excitonically coupled linear chain of four Pchlide chromophores, using exciton theory with phenomenological Gaussian line shapes and without energetic disorder. A refined multiexciton model that includes static disorder is applied to fit the experimental power-dependent transient absorption spectra of aqueous protochlorophyllide and the kinetics for delay times up to 20 ps after photoexcitation. We show that population up to the 4-exciton manifold is sufficient to explain the pronounced saturation of the bleaching and the shape changes in the instantaneous, t = 0.2 ps transient spectra when the pulse energy is increased from 10 to 430 nJ per pulse. The decay of the multiexciton manifold is relatively slow and is preceded by a spectroscopically distinct process. We suggest that the exciton states in the Pchlide aggregates are mixed with charge-transfer states (CTS) and that the population and repopulation of the CTS coupled to the exciton states explains the relatively slow decay of the multiexciton manifold. The relevance of our results to the optical properties and dynamics of natural photosynthetic complexes and the possible physical origin of CTS formation are discussed.
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Affiliation(s)
- Olga A Sytina
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands.
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30
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Di Donato M, van Wilderen LJGW, Van Stokkum IHM, Stuart TC, Kennis JTM, Hellingwerf KJ, van Grondelle R, Groot ML. Proton transfer events in GFP. Phys Chem Chem Phys 2011; 13:16295-305. [PMID: 21847481 DOI: 10.1039/c1cp20387h] [Citation(s) in RCA: 35] [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: 12/30/2022]
Abstract
Proton transfer is one of the most important elementary processes in biology. Green fluorescent protein (GFP) serves as an important model system to elucidate the mechanistic details of this reaction, because in GFP proton transfer can be induced by light absorption. Illumination initiates proton transfer through a 'proton-wire', formed by the chromophore (the proton donor), water molecule W22, Ser205 and Glu222 (the acceptor), on a picosecond time scale. To obtain a more refined view of this process, we have used a combined approach of time resolved mid-infrared spectroscopy and visible pump-dump-probe spectroscopy to resolve with atomic resolution how and how fast protons move through this wire. Our results indicate that absorption of light by GFP induces in 3 ps (10 ps in D(2)O) a shift of the equilibrium positions of all protons in the H-bonded network, leading to a partial protonation of Glu222 and to a so-called low barrier hydrogen bond (LBHB) for the chromophore's proton, giving rise to dual emission at 475 and 508 nm. This state is followed by a repositioning of the protons on the wire in 10 ps (80 ps in D(2)O), ultimately forming the fully deprotonated chromophore and protonated Glu222.
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Affiliation(s)
- Mariangela Di Donato
- Department of Physics and Astronomy, VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.
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31
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Rupenyan AB, Vreede J, van Stokkum IHM, Hospes M, Kennis JTM, Hellingwerf KJ, Groot ML. Proline 68 enhances photoisomerization yield in photoactive yellow protein. J Phys Chem B 2011; 115:6668-77. [PMID: 21542640 DOI: 10.1021/jp112113s] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In proteins and enzymes, the local environment of an active cofactor plays an important role in controlling the outcome of a functional reaction. In photoactive yellow protein (PYP), it ensures photoisomerization of the chromophore, a prerequisite for formation of a signaling state. PYP is the prototype of a PAS domain, and the preferred model system for the studies of molecular mechanisms of biological light sensing. We investigated the effect of replacing proline-68, positioned near but not in direct contact with the chromophore, with other neutral amino acids (alanine, glycine, and valine), using ultrafast spectroscopy probing the visible and the mid-IR spectral regions, and molecular simulation to understand the interactions tuning the efficiency of light signaling. Transient absorption measurements indicate that the quantum yield of isomerization in the mutants is lower than the yield observed for the wild type. Subpicosecond mid-IR spectra and molecular dynamics simulations of the four proteins reveal that the hydrogen bond interactions around the chromophore and the access of water molecules in the active site of the protein determine the efficiency of photoisomerization. The mutants provide additional hydrogen bonds to the chromophore, directly and by allowing more water molecules access to its binding pocket. We conclude that proline-68 in the wild type protein optimizes the yield of photochemistry by maintaining a weak hydrogen bond with the chromophore, at the same time restraining the entrance of water molecules close to the alkylic part of pCa. This study provides a molecular basis for the structural optimization of biological light sensing.
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Affiliation(s)
- Alisa B Rupenyan
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, Amsterdam, The Netherlands.
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32
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Sytina OA, van Stokkum IHM, van Grondelle R, Groot ML. Single and multi-exciton dynamics in aqueous protochlorophyllide aggregates. J Phys Chem A 2010; 115:3936-46. [PMID: 21171640 DOI: 10.1021/jp108317u] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [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
In plants, the oxidoreductase enzyme POR reduces protochlorophyllide (Pchlide) into chlorophyllide (Chlide), using NADPH as a cofactor. The reduction involves the transfer of two electrons and two protons to the C17═C18 double bond of Pchlide, and the reaction is initiated by the absorption of light by Pchlide itself. In this work we have studied the excited state dynamics of Pchlide dissolved in water, where it forms excitonically coupled aggregates, by ultrafast time-resolved transient absorption and fluorescence experiments performed in the 480-720 nm visible region and in the 1780-1590 cm(-1) mid-IR region. The ground state visible absorption spectrum of aqueous Pchlide red shifts and broadens in comparison to the spectrum of monomeric Pchlide in organic solvents. The population of the one-exciton state occurs at low excitation densities, of <1 photon per aggregate. We characterized the multiexciton manifolds spectra by measuring the absorption difference spectra at increasingly higher photon densities. The multiexciton states are characterized by blue-shifted stimulated emission and red-shifted excited state absorption in comparison to those of the one-exciton manifold. The relaxation dynamics of the multiexciton manifolds into the one-exciton manifold is found to occur in ∼10 ps. This surprisingly slow rate we suggest is due to the intrinsic charge transfer character of the PChlide excited state that leads to solvation, stabilizing the CT state, and subsequent charge recombination, which limits the exciton relaxation.
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Affiliation(s)
- Olga A Sytina
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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33
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Sytina OA, Alexandre MT, Heyes DJ, Hunter CN, Robert B, van Grondelle R, Groot ML. Enzyme activation and catalysis: characterisation of the vibrational modes of substrate and product in protochlorophyllide oxidoreductase. Phys Chem Chem Phys 2010; 13:2307-13. [PMID: 21103538 DOI: 10.1039/c0cp01686a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The light-dependent reduction of protochlorophyllide, a key step in the synthesis of chlorophyll, is catalyzed by the enzyme protochlorophyllide oxidoreductase (POR) and requires two photons (O. A. Sytina et al., Nature, 2008, 456, 1001-1008). The first photon activates the enzyme-substrate complex, a subsequent second photon initiates the photochemistry by triggering the formation of a catalytic intermediate. These two events are characterized by different spectral changes in the infra-red spectral region. Here, we investigate the vibrational frequencies of the POR-bound and unbound substrate, and product, and thus provide a detailed assignment of the spectral changes in the 1800-1250 cm(-1) region associated with the catalytic conversion of PChlide:NADPH:TyrOH into Chlide:NADP(+):TyrO(-). Fluorescence line narrowed spectra of the POR-bound Pchlide reveal a C=O keto group downshifted by more than 20 cm(-1) to a relatively low vibrational frequency of 1653 cm(-1), as compared to the unbound Pchlide, indicating that binding of the chromophore to the protein occurs via strong hydrogen bond(s). The frequencies of the C=C vibrational modes are consistent with a six-coordinated state of the POR-bound Pchlide, suggesting that there are two coordination interactions between the central Mg atom of the chromophore and protein residues, and/or a water molecule. The frequencies of the C=C vibrational modes of Chlide are consistent with a five-coordinated state, indicating a single interaction between the central Mg atom of the chromophore and a water molecule. Rapid-scan FTIR measurements on the Pchlide:POR:NADPH complex at 4 cm(-1) spectral resolution reveal a new band in the 1670 cm(-1) region. The FTIR spectra of the enzyme activation phase indicate involvement of a nucleotide-binding structural motif, and an increased exposure of the protein to solvent after activation.
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Affiliation(s)
- Olga A Sytina
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.
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Sytina OA, van Stokkum IHM, Heyes DJ, Hunter CN, van Grondelle R, Groot ML. Protochlorophyllide excited-state dynamics in organic solvents studied by time-resolved visible and mid-infrared spectroscopy. J Phys Chem B 2010; 114:4335-44. [PMID: 20205376 DOI: 10.1021/jp9089326] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Protochlorophyllide (PChlide) is a precursor in the biosynthesis of chlorophyll. Complexed with NADPH to the enzyme protochlorophyllide oxidoreductase (POR), it is reduced to chlorophyllide, a process that occurs via a set of spectroscopically distinct intermediate states and is initiated from the excited state of PChlide. To obtain a better understanding of these catalytic events, we characterized the excited state dynamics of PChlide in the solvents tetrahydrofuran (THF), methanol, and Tris/Triton buffer using ultrafast transient absorption in the visible and mid-infrared spectral regions and time-resolved fluorescence emission experiments. For comparison, we present time-resolved transient absorption measurements of chlorophyll a in THF. From the combined analysis of these experiments, we derive that during the 2-3 ns excited state lifetime an extensive multiphasic quenching of the emission occurs due to solvation of the excited state, which is in agreement with the previously proposed internal charge transfer (ICT) character of the S1 state ( Zhao , G. J. ; Han , K. L. Biophys. J. 2008 , 94 , 38 ). The solvation process in methanol occurs in conjunction with a strengthening of a hydrogen bond to the Pchlide keto carbonyl group. We demonstrate that the internal conversion from the S2 to S1 excited states is remarkably slow and stretches out on to the 700 fs time scale, causing a rise of blue-shifted signals in the transient absorption and a gain of emission in the time-resolved fluorescence. A triplet state is populated on the nanosecond time scale with a maximal yield of approximately 23%. The consequences of these observations for the catalytic pathway and the role of the triplet and ICT state in activation of the enzyme are discussed.
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Affiliation(s)
- Olga A Sytina
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands.
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35
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Stahl AD, Di Donato M, van Stokkum I, van Grondelle R, Groot ML. A femtosecond visible/visible and visible/mid-infrared transient absorption study of the light harvesting complex II. Biophys J 2010; 97:3215-23. [PMID: 20006959 DOI: 10.1016/j.bpj.2009.09.037] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Revised: 08/11/2009] [Accepted: 09/15/2009] [Indexed: 01/11/2023] Open
Abstract
Light harvesting complex II (LHCII) is the most abundant protein in the thylakoid membrane of higher plants and green algae. LHCII acts to collect solar radiation, transferring this energy mainly toward photosystem II, with a smaller amount going to photosystem I; it is then converted into a chemical, storable form. We performed time-resolved femtosecond visible pump/mid-infrared probe and visible pump/visible probe absorption difference spectroscopy on purified LHCII to gain insight into the energy transfer in this complex occurring in the femto-picosecond time regime. We find that information derived from mid-infrared spectra, together with structural and modeling information, provides a unique visualization of the flow of energy via the bottleneck pigment chlorophyll a604.
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Affiliation(s)
- Andreas D Stahl
- Faculty of Sciences, Department of Physics and Astronomy, VU University Amsterdam, Amsterdam, The Netherlands
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36
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Rupenyan A, van Stokkum IHM, Arents JC, van Grondelle R, Hellingwerf KJ, Groot ML. Reaction pathways of photoexcited retinal in proteorhodopsin studied by pump-dump-probe spectroscopy. J Phys Chem B 2010; 113:16251-6. [PMID: 19928893 DOI: 10.1021/jp9065289] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Proteorhodopsin (pR) is a membrane-embedded proton pump from the microbial rhodopsin family. Light absorption by its retinal chromophore initiates a photocycle, driven by trans/cis isomerization on the femtosecond to picosecond time scales. Here, we report a study on the photoisomerization dynamics of the retinal chromophore of pR, using dispersed ultrafast pump-dump-probe spectroscopy. The application of a pump pulse initiates the photocycle, and with an appropriately tuned dump pulse applied at a time delay after the dump, the molecules in the initial stages of the photochemical process can be de-excited and driven back to the ground state. In this way, we were able to resolve an intermediate on the electronic ground state that represents chromophores that are unsuccessful in isomerization. In particular, the fractions of molecules that undergo slow isomerization (20 ps) have a high probability to enter this state rather than the isomerized K-state. On the ground state reaction surface, return to the stable ground state conformation via a structural or vibrational relaxation occurs in 2-3 ps. Inclusion of this intermediate in the kinetic scheme led to more consistent spectra of the retinal-excited state, and to a more accurate estimation of the quantum yield of isomerization (Phi = 0.4 at pH 6).
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Affiliation(s)
- Alisa Rupenyan
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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37
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Bonetti C, Alexandre MTA, van Stokkum IHM, Hiller RG, Groot ML, van Grondelle R, Kennis JTM. Identification of excited-state energy transfer and relaxation pathways in the peridinin–chlorophyll complex: an ultrafast mid-infrared study. Phys Chem Chem Phys 2010; 12:9256-66. [DOI: 10.1039/b923695c] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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38
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Witte S, Baclayon M, Peterman EJG, Toonen RFG, Mansvelder HD, Groot ML. Single-shot two-dimensional full-range optical coherence tomography achieved by dispersion control. Opt Express 2009; 17:11335-49. [PMID: 19582048 DOI: 10.1364/oe.17.011335] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
We present a full-range Fourier-domain optical coherence tomography (OCT) system that is capable of acquiring two-dimensional images of living tissue in a single shot. By using line illumination of the sample in combination with a two-dimensional imaging spectrometer, 1040 depth scans are performed simultaneously on a sub-millisecond timescale. Furthermore, we demonstrate an easy and flexible real-time single-shot technique for full-range (complex-conjugate cancelled) OCT imaging that is compatible with both two-dimensional as well as ultrahigh-resolution OCT. By implementing a dispersion imbalance between reference and sample arms of the interferometer, we eliminate the complex-conjugate signal through numerical dispersion compensation, effectively increasing the useful depth range by a factor of two. The system allows us to record 6.7 x 3.2 mm images at 5 microm depth resolution in 0.2 ms. Data postprocessing requires only 4 s. We demonstrate the capability of our system by imaging the anterior chamber of a mouse eye in vitro, as well as human skin in vivo.
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Affiliation(s)
- S Witte
- Department of Physics and Astronomy, Faculty of Sciences, VU University, Amsterdam, The Netherlands.
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39
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Rupenyan A, Commandeur J, Groot ML. CO Photodissociation Dynamics in Cytochrome P450BM3 Studied by Subpicosecond Visible and Mid-Infrared Spectroscopy. Biochemistry 2009; 48:6104-10. [DOI: 10.1021/bi900351m] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [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)
- Alisa Rupenyan
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
| | - Jan Commandeur
- Department of Pharmacochemistry, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
| | - Marie Louise Groot
- Department of Physics and Astronomy, Faculty of Sciences, VU University Amsterdam, Amsterdam, The Netherlands
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40
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Sytina OA, Heyes DJ, Hunter CN, Alexandre MT, van Stokkum IHM, van Grondelle R, Groot ML. Conformational changes in an ultrafast light-driven enzyme determine catalytic activity. Nature 2009; 456:1001-4. [PMID: 19092933 DOI: 10.1038/nature07354] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Accepted: 08/15/2008] [Indexed: 11/09/2022]
Abstract
The role of conformational changes in explaining the huge catalytic power of enzymes is currently one of the most challenging questions in biology. Although it is now widely regarded that enzymes modulate reaction rates by means of short- and long-range protein motions, it is almost impossible to distinguish between conformational changes and catalysis. We have solved this problem using the chlorophyll biosynthetic enzyme NADPH:protochlorophyllide (Pchlide) oxidoreductase, which catalyses a unique light-driven reaction involving hydride and proton transfers. Here we report that prior excitation of the enzyme-substrate complex with a laser pulse induces a more favourable conformation of the active site, enabling the coupled hydride and proton transfer reactions to occur. This effect, which is triggered during the Pchlide excited-state lifetime and persists on a long timescale, switches the enzyme into an active state characterized by a high rate and quantum yield of formation of a catalytic intermediate. The corresponding spectral changes in the mid-infrared following the absorption of one photon reveal significant conformational changes in the enzyme, illustrating the importance of flexibility and dynamics in the structure of enzymes for their function.
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Affiliation(s)
- Olga A Sytina
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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van Wilderen LJGW, Key JM, Van Stokkum IHM, van Grondelle R, Groot ML. Dynamics of Carbon Monoxide Photodissociation in Bradyrhizobium japonicum FixL Probed by Picosecond Midinfrared Spectroscopy. J Phys Chem B 2008; 113:3292-7. [DOI: 10.1021/jp8050565] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Luuk J. G. W. van Wilderen
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands and Laboratory for Microbiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Jason M. Key
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands and Laboratory for Microbiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Ivo H. M. Van Stokkum
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands and Laboratory for Microbiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Rienk van Grondelle
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands and Laboratory for Microbiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
| | - Marie Louise Groot
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands and Laboratory for Microbiology, Swammerdam Institute for Life Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, The Netherlands
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Pawlowicz NP, van Grondelle R, van Stokkum IHM, Breton J, Jones MR, Groot ML. Identification of the first steps in charge separation in bacterial photosynthetic reaction centers of Rhodobacter sphaeroides by ultrafast mid-infrared spectroscopy: electron transfer and protein dynamics. Biophys J 2008; 95:1268-84. [PMID: 18424493 PMCID: PMC2479572 DOI: 10.1529/biophysj.108.130880] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2008] [Accepted: 03/31/2008] [Indexed: 01/08/2023] Open
Abstract
Time-resolved visible pump/mid-infrared (mid-IR) probe spectroscopy in the region between 1600 and 1800 cm(-1) was used to investigate electron transfer, radical pair relaxation, and protein relaxation at room temperature in the Rhodobacter sphaeroides reaction center (RC). Wild-type RCs both with and without the quinone electron acceptor Q(A), were excited at 600 nm (nonselective excitation), 800 nm (direct excitation of the monomeric bacteriochlorophyll (BChl) cofactors), and 860 nm (direct excitation of the dimer of primary donor (P) BChls (P(L)/P(M))). The region between 1600 and 1800 cm(-1) encompasses absorption changes associated with carbonyl (C=O) stretch vibrational modes of the cofactors and protein. After photoexcitation of the RC the primary electron donor P excited singlet state (P*) decayed on a timescale of 3.7 ps to the state P(+)B(L)(-) (where B(L) is the accessory BChl electron acceptor). This is the first report of the mid-IR absorption spectrum of P(+)B(L)(-); the difference spectrum indicates that the 9-keto C=O stretch of B(L) is located around 1670-1680 cm(-1). After subsequent electron transfer to the bacteriopheophytin H(L) in approximately 1 ps, the state P(+)H(L)(-) was formed. A sequential analysis and simultaneous target analysis of the data showed a relaxation of the P(+)H(L)(-) radical pair on the approximately 20 ps timescale, accompanied by a change in the relative ratio of the P(L)(+) and P(M)(+) bands and by a minor change in the band amplitude at 1640 cm(-1) that may be tentatively ascribed to the response of an amide C=O to the radical pair formation. We conclude that the drop in free energy associated with the relaxation of P(+)H(L)(-) is due to an increased localization of the electron hole on the P(L) half of the dimer and a further consequence is a reduction in the electrical field causing the Stark shift of one or more amide C=O oscillators.
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Affiliation(s)
- Natalia P Pawlowicz
- Faculty of Sciences, Department of Physics and Astronomy, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
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Di Donato M, van Grondelle R, van Stokkum IHM, Groot ML. Excitation Energy Transfer in the Photosystem II Core Antenna Complex CP43 Studied by Femtosecond Visible/Visible and Visible/Mid-Infrared Pump Probe Spectroscopy. J Phys Chem B 2007; 111:7345-52. [PMID: 17550278 DOI: 10.1021/jp068315+] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [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: 11/29/2022]
Abstract
Excitation energy transfer in the Photosystem II core antenna complex CP43 has been investigated by vis/vis and vis/mid-IR pump-probe spectroscopy with the aim of understanding the relation between the dynamics of energy transfer and the structural arrangement of individual chlorophyll molecules within the protein. Energy transfer was found to occur on time scales of 250 fs, 2-4 ps, and 10-12 ps. The vis/mid-IR difference spectra show that the excitation is initially distributed over chlorophylls located in environments with different polarity, since two 9-keto C=O stretching bleachings, at 1691 and 1677 cm-1, are observable at early delay times. Positive signals in the initial difference spectra around 1750 and 1720 cm-1 indicate the presence of a charge transfer state between strongly interacting chlorophylls. We conclude, both from the spectral behavior in the visible when the annihilation processes are increased and from the vis/mid-IR data, that there are two pigments (one absorbing around 670 nm and one at 683 nm) which are not connected to the other pigments on a time scale faster than 10-20 ps. Since, in the IR, on a 10 ps time scale the population of the 1691 cm-1 mode almost disappears, while the 1677 cm-1 mode is still significantly populated, we can conclude that at least some of the red absorbing pigments are located in a polar environment, possibly forming H-bonds with the surrounding protein.
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Affiliation(s)
- Mariangela Di Donato
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands
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44
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Groot ML, van Wilderen LJGW, Di Donato M. Time-resolved methods in biophysics. 5. Femtosecond time-resolved and dispersed infrared spectroscopy on proteins. Photochem Photobiol Sci 2007; 6:501-7. [PMID: 17487299 DOI: 10.1039/b613023b] [Citation(s) in RCA: 49] [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: 01/16/2023]
Abstract
In this contribution we describe how femtosecond time-resolved infrared spectroscopy provides insight into the function and dynamics of pigment-protein complexes, and what the technical requirements are to perform such experiments. We further discuss a few examples of experiments performed on the photoactive yellow protein and photosynthetic complexes in more detail.
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Affiliation(s)
- Marie Louise Groot
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands.
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45
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van Wilderen LJGW, van der Horst MA, van Stokkum IHM, Hellingwerf KJ, van Grondelle R, Groot ML. Ultrafast infrared spectroscopy reveals a key step for successful entry into the photocycle for photoactive yellow protein. Proc Natl Acad Sci U S A 2006; 103:15050-5. [PMID: 17015839 PMCID: PMC1940041 DOI: 10.1073/pnas.0603476103] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [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: 11/18/2022] Open
Abstract
Photoactive proteins such as PYP (photoactive yellow protein) are generally accepted as model systems for studying protein signal state formation. PYP is a blue-light sensor from the bacterium Halorhodospira halophila. The formation of PYP's signaling state is initiated by trans-cis isomerization of the p-coumaric acid chromophore upon the absorption of light. The quantum yield of signaling state formation is approximately 0.3. Using femtosecond visible pump/mid-IR probe spectroscopy, we investigated the structure of the very short-lived ground state intermediate (GSI) that results from an unsuccessful attempt to enter the photocycle. This intermediate and the first stable GSI on pathway into the photocycle, I0, both have a mid-IR difference spectrum that is characteristic of a cis isomer, but only the I0 intermediate has a chromophore with a broken hydrogen bond with the backbone N atom of Cys-69. We suggest, therefore, that breaking this hydrogen bond is decisive for a successful entry into the photocycle. The chromophore also engages in a hydrogen-bonding network by means of its phenolate group with residues Tyr-42 and Glu-46. We have investigated the role of this hydrogen bond by exchanging the H bond-donating residue Glu-46 with the weaker H bond-donating glutamine (i.e., Gln-46). We have observed that this mutant exhibits virtually identical kinetics and product yields as WT PYP, even though during the I0-to-I1 transition, on the 800-ps time scale, the hydrogen bond of the chromophore with Gln-46 is broken, whereas this hydrogen bond remains intact with Glu-46.
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Affiliation(s)
- L J G W van Wilderen
- Department of Physics and Astronomy, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands.
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Groot ML, Pawlowicz NP, van Wilderen LJGW, Breton J, van Stokkum IHM, van Grondelle R. Initial electron donor and acceptor in isolated Photosystem II reaction centers identified with femtosecond mid-IR spectroscopy. Proc Natl Acad Sci U S A 2005; 102:13087-92. [PMID: 16135567 PMCID: PMC1196200 DOI: 10.1073/pnas.0503483102] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.3] [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: 04/27/2005] [Indexed: 11/18/2022] Open
Abstract
Despite the apparent similarity between the plant Photosystem II reaction center (RC) and its purple bacterial counterpart, we show in this work that the mechanism of charge separation is very different for the two photosynthetic RCs. By using femtosecond visible-pump-mid-infrared probe spectroscopy in the region of the chlorophyll ester and keto modes, between 1,775 and 1,585 cm(-1), with 150-fs time resolution, we show that the reduction of pheophytin occurs on a 0.6- to 0.8-ps time scale, whereas P+, the precursor state for water oxidation, is formed after approximately 6 ps. We conclude therefore that in the Photosystem II RC the primary charge separation occurs between the "accessory chlorophyll" Chl(D1) and the pheophytin on the so-called active branch.
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Affiliation(s)
- Marie Louise Groot
- Faculty of Sciences, Vrije Universiteit, 1081 HV, Amsterdam, The Netherlands.
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47
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Groot ML, Breton J, van Wilderen LJGW, Dekker JP, van Grondelle R. Femtosecond Visible/Visible and Visible/Mid-IR Pump−Probe Study of the Photosystem II Core Antenna Complex CP47. J Phys Chem B 2004. [DOI: 10.1021/jp037966s] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [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)
- Marie Louise Groot
- Faculty of Sciences, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands, and Service de Bioénergétique, Bât. 532, CEA-Saclay, 91191 Gif-sur-Yvette, France
| | - Jacques Breton
- Faculty of Sciences, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands, and Service de Bioénergétique, Bât. 532, CEA-Saclay, 91191 Gif-sur-Yvette, France
| | - Luuk J. G. W. van Wilderen
- Faculty of Sciences, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands, and Service de Bioénergétique, Bât. 532, CEA-Saclay, 91191 Gif-sur-Yvette, France
| | - Jan P. Dekker
- Faculty of Sciences, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands, and Service de Bioénergétique, Bât. 532, CEA-Saclay, 91191 Gif-sur-Yvette, France
| | - Rienk van Grondelle
- Faculty of Sciences, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands, and Service de Bioénergétique, Bât. 532, CEA-Saclay, 91191 Gif-sur-Yvette, France
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48
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Groot ML, van Wilderen LJGW, Larsen DS, van der Horst MA, van Stokkum IHM, Hellingwerf KJ, van Grondelle R. Initial steps of signal generation in photoactive yellow protein revealed with femtosecond mid-infrared spectroscopy. Biochemistry 2003; 42:10054-9. [PMID: 12939133 DOI: 10.1021/bi034878p] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.4] [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: 11/28/2022]
Abstract
Photoactive yellow protein (PYP) is a bacterial blue light sensor that induces Halorhodospira halophila to swim away from intense blue light. Light absorption by PYP's intrinsic chromophore, p-coumaric acid, leads to the initiation of a photocycle that comprises several distinct intermediates. Here we describe the initial structural changes of the chromophore and its nearby amino acids, using visible pump/mid-infrared probe spectroscopy. Upon photoexcitation, the trans bands of the chromophore are bleached, and shifts of the phenol ring bands occur. The latter are ascribed to charge translocation, which probably plays an essential role in driving the trans to cis isomerization process. We conclude that breaking of the hydrogen bond of the chromophore's C=O group with amino acid Cys69 and formation of a stable cis ground state occur in approximately 2 ps. Dynamic changes also include rearrangements of the hydrogen-bonding network of the amino acids around the chromophore. Relaxation of the coumaryl tail of the chromophore occurs in 0.9-1 ns, which event we identify with the I(0) to I(1) transition observed in visible spectroscopy.
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Affiliation(s)
- Marie Louise Groot
- Faculty of Sciences, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands.
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49
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Heyes DJ, Hunter CN, van Stokkum IHM, van Grondelle R, Groot ML. Ultrafast enzymatic reaction dynamics in protochlorophyllide oxidoreductase. Nat Struct Mol Biol 2003; 10:491-2. [PMID: 12730687 DOI: 10.1038/nsb929] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2003] [Accepted: 04/10/2003] [Indexed: 11/09/2022]
Abstract
The reaction catalyzed by the light-driven enzyme protochlorophyllide oxidoreductase (POR) has been initiated with a 50-fs laser pulse. We show that the catalytic mechanism, involving proton and hydride transfers, proceeds with time constants of 3 ps and 400 ps. It is known that catalysis by POR involves thermally excited protein dynamics; our results show that these molecular motions occur on an ultrafast timescale.
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Affiliation(s)
- Derren J Heyes
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
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50
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Groot ML, Frese RN, de Weerd FL, Bromek K, Pettersson A, Peterman EJ, van Stokkum IH, van Grondelle R, Dekker JP. Spectroscopic properties of the CP43 core antenna protein of photosystem II. Biophys J 1999; 77:3328-40. [PMID: 10585955 PMCID: PMC1300604 DOI: 10.1016/s0006-3495(99)77164-x] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.0] [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: 10/21/2022] Open
Abstract
CP43 is a chlorophyll-protein complex that funnels excitation energy from the main light-harvesting system of photosystem II to the photochemical reaction center. We purified CP43 from spinach photosystem II membranes in the presence of the nonionic detergent n-dodecyl-beta,D-maltoside and recorded its spectroscopic properties at various temperatures between 4 and 293 K by a number of polarized absorption and fluorescence techniques, fluorescence line narrowing, and Stark spectroscopy. The results indicate two "red" states in the Q(y) absorption region of the chlorophylls. The first peaks at 682.5 nm at 4 K, has an extremely narrow bandwidth with a full width at half-maximum of approximately 2.7 nm (58 cm(-1)) at 4 K, and has the oscillator strength of a single chlorophyll. The second peaks at approximately 679 nm, has a much broader bandshape, is caused by several excitonically interacting chlorophylls, and is responsible for all 4 K absorption at wavelengths longer than 685 nm. The Stark spectrum of CP43 resembles the first derivative of the absorption spectrum and has an exceptionally small overall size, which we attribute to opposing orientations of the monomer dipole moments of the excitonically coupled pigments.
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Affiliation(s)
- M L Groot
- Division of Physics and Astronomy, Institute of Molecular Biological Sciences, Vrije Universiteit, 1081 HV Amsterdam, The Netherlands
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