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Buhrke D. The impact of chromophore choice on the assembly kinetics and primary photochemistry of a red/green cyanobacteriochrome. Phys Chem Chem Phys 2021; 23:20867-20874. [PMID: 34374395 PMCID: PMC8479780 DOI: 10.1039/d1cp02696h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/04/2021] [Indexed: 11/24/2022]
Abstract
Cyanobacteriochromes (CBCRs) are bi-stable photoreceptor proteins with high potential for biotechnological applications. Most of these proteins utilize phycocyanobilin (PCB) as a light-sensing co-factor, which is unique to cyanobacteria, but some variants also incorporate biliverdin (BV). The latter are of particular interest for biotechnology due to the natural abundance and red-shifted absorption of BV. Here, AmI-g2 was investigated, a CBCR capable of binding both PCB and BV. The assembly kinetics and primary photochemistry of AmI-g2 with both chromophores were studied in vitro. The assembly reaction with PCB is roughly 10× faster than BV, and the formation of a non-covalent intermediate was identified as the rate-limiting step in the case of BV. This step is fast for PCB, where the formation of the covalent thioether bond between AmI-g2 and PCB becomes rate-limiting. The photochemical quantum yields of the forward and backward reactions of AmI-g2 were estimated and discussed in the context of homologous CBCRs.
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Affiliation(s)
- David Buhrke
- Department of Chemistry, University of Zürich, Zürich, Switzerland.
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2
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Ultrafast proton release reaction and primary photochemistry of phycocyanobilin in solution observed with fs-time-resolved mid-IR and UV/Vis spectroscopy. Photochem Photobiol Sci 2021; 20:715-732. [PMID: 34002345 DOI: 10.1007/s43630-021-00045-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 04/16/2021] [Indexed: 12/27/2022]
Abstract
Deactivation processes of photoexcited (λex = 580 nm) phycocyanobilin (PCB) in methanol were investigated by means of UV/Vis and mid-IR femtosecond (fs) transient absorption (TA) as well as static fluorescence spectroscopy, supported by density-functional-theory calculations of three relevant ground state conformers, PCBA, PCBB and PCBC, their relative electronic state energies and normal mode vibrational analysis. UV/Vis fs-TA reveals time constants of 2.0, 18 and 67 ps, describing decay of PCBB*, of PCBA* and thermal re-equilibration of PCBA, PCBB and PCBC, respectively, in line with the model by Dietzek et al. (Chem Phys Lett 515:163, 2011) and predecessors. Significant substantiation and extension of this model is achieved first via mid-IR fs-TA, i.e. identification of molecular structures and their dynamics, with time constants of 2.6, 21 and 40 ps, respectively. Second, transient IR continuum absorption (CA) is observed in the region above 1755 cm-1 (CA1) and between 1550 and 1450 cm-1 (CA2), indicative for the IR absorption of highly polarizable protons in hydrogen bonding networks (X-H…Y). This allows to characterize chromophore protonation/deprotonation processes, associated with the electronic and structural dynamics, on a molecular level. The PCB photocycle is suggested to be closed via a long living (> 1 ns), PCBC-like (i.e. deprotonated), fluorescent species.
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Minic S, Stanic-Vucinic D, Radomirovic M, Radibratovic M, Milcic M, Nikolic M, Cirkovic Velickovic T. Characterization and effects of binding of food-derived bioactive phycocyanobilin to bovine serum albumin. Food Chem 2018; 239:1090-1099. [DOI: 10.1016/j.foodchem.2017.07.066] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 06/21/2017] [Accepted: 07/13/2017] [Indexed: 11/30/2022]
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4
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Dagnino-Leone J, Figueroa M, Mella C, Vorphal MA, Kerff F, Vásquez AJ, Bunster M, Martínez-Oyanedel J. Structural models of the different trimers present in the core of phycobilisomes from Gracilaria chilensis based on crystal structures and sequences. PLoS One 2017; 12:e0177540. [PMID: 28542288 PMCID: PMC5436742 DOI: 10.1371/journal.pone.0177540] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 04/28/2017] [Indexed: 11/25/2022] Open
Abstract
Phycobilisomes (PBS) are accessory light harvesting protein complexes that directionally transfer energy towards photosystems. Phycobilisomes are organized in a central core and rods radiating from it. Components of phycobilisomes in Gracilaria chilensis (Gch) are Phycobiliproteins (PBPs), Phycoerythrin (PE), and Phycocyanin (PC) in the rods, while Allophycocyanin (APC) is found in the core, and linker proteins (L). The function of such complexes depends on the structure of each component and their interaction. The core of PBS from cyanobacteria is mainly composed by cylinders of trimers of α and β subunits forming heterodimers of Allophycocyanin, and other components of the core including subunits αII and β18. As for the linkers, Linker core (LC) and Linker core membrane (LCM) are essential for the final emission towards photoreaction centers. Since we have previously focused our studies on the rods of the PBS, in the present article we investigated the components of the core in the phycobilisome from the eukaryotic algae, Gracilaria chilensis and their organization into trimers. Transmission electron microscopy provided the information for a three cylinders core, while the three dimensional structure of Allophycocyanin purified from Gch was determined by X-ray diffraction method and the biological unit was determined as a trimer by size exclusion chromatography. The protein sequences of all the components of the core were obtained by sequencing the corresponding genes and their expression confirmed by transcriptomic analysis. These subunits have seldom been reported in red algae, but not in Gracilaria chilensis. The subunits not present in the crystallographic structure were modeled to build the different composition of trimers. This article proposes structural models for the different types of trimers present in the core of phycobilisomes of Gch as a first step towards the final model for energy transfer in this system.
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Affiliation(s)
- Jorge Dagnino-Leone
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Maximiliano Figueroa
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Claudia Mella
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - María Alejandra Vorphal
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Frédéric Kerff
- Centre d'Ingéniérie des Protéines, Université de Liège, Liège, Belgium
| | - Aleikar José Vásquez
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - Marta Bunster
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
| | - José Martínez-Oyanedel
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Concepción, Chile
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5
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Radibratovic M, Minic S, Stanic-Vucinic D, Nikolic M, Milcic M, Cirkovic Velickovic T. Stabilization of Human Serum Albumin by the Binding of Phycocyanobilin, a Bioactive Chromophore of Blue-Green Alga Spirulina: Molecular Dynamics and Experimental Study. PLoS One 2016; 11:e0167973. [PMID: 27959940 PMCID: PMC5154526 DOI: 10.1371/journal.pone.0167973] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 11/24/2016] [Indexed: 11/18/2022] Open
Abstract
Phycocyanobilin (PCB) binds with high affinity (2.2 x 106 M-1 at 25°C) to human serum albumin (HSA) at sites located in IB and IIA subdomains. The aim of this study was to examine effects of PCB binding on protein conformation and stability. Using 300 ns molecular dynamics (MD) simulations, UV-VIS spectrophotometry, CD, FT-IR, spectrofluorimetry, thermal denaturation and susceptibility to trypsin digestion, we studied the effects of PCB binding on the stability and rigidity of HSA, as well as the conformational changes in PCB itself upon binding to the protein. MD simulation results demonstrated that HSA with PCB bound at any of the two sites showed greater rigidity and lower overall and individual domain flexibility compared to free HSA. Experimental data demonstrated an increase in the α-helical content of the protein and thermal and proteolytic stability upon ligand binding. PCB bound to HSA undergoes a conformational change to a more elongated conformation in the binding pockets of HSA. PCB binding to HSA stabilizes the structure of this flexible transport protein, making it more thermostable and resistant to proteolysis. The results from this work explain at molecular level, conformational changes and stabilization of HSA structure upon ligand binding. The resultant increased thermal and proteolytic stability of HSA may provide greater longevity to HSA in plasma.
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Affiliation(s)
- Milica Radibratovic
- Institute of Chemistry, Technology and Metallurgy - Center for Chemistry, University of Belgrade, Belgrade, Serbia
| | - Simeon Minic
- Center of Excellence for Molecular Food Sciences, University of Belgrade - Faculty of Chemistry, Belgrade, Serbia
| | - Dragana Stanic-Vucinic
- Center of Excellence for Molecular Food Sciences, University of Belgrade - Faculty of Chemistry, Belgrade, Serbia
| | - Milan Nikolic
- Center of Excellence for Molecular Food Sciences, University of Belgrade - Faculty of Chemistry, Belgrade, Serbia
- Department of Biochemistry, University of Belgrade - Faculty of Chemistry, Belgrade, Serbia
| | - Milos Milcic
- Department of Inorganic Chemistry, University of Belgrade - Faculty of Chemistry, Belgrade, Serbia
- Center for Computational Chemistry and Bioinformatics, University of Belgrade - Faculty of Chemistry, Belgrade, Serbia
- * E-mail: (TCV); (MM)
| | - Tanja Cirkovic Velickovic
- Center of Excellence for Molecular Food Sciences, University of Belgrade - Faculty of Chemistry, Belgrade, Serbia
- Ghent University Global Campus, Yeonsu-gu, Incheon, South Korea
- Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
- * E-mail: (TCV); (MM)
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Singer P, Fey S, Göller AH, Hermann G, Diller R. Femtosecond Dynamics in the Lactim Tautomer of Phycocyanobilin: A Long-Wavelength Absorbing Model Compound for the Phytochrome Chromophore. Chemphyschem 2014; 15:3824-31. [DOI: 10.1002/cphc.201402383] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Indexed: 11/11/2022]
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7
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Watermann T, Elgabarty H, Sebastiani D. Phycocyanobilin in solution – a solvent triggered molecular switch. Phys Chem Chem Phys 2014; 16:6146-52. [DOI: 10.1039/c3cp54307b] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The chromophore phycocyanobilin changes its spectroscopic behaviour upon solvent change. Our calculations trace this effect back to conformational switching, induced by changes in the hydrogen bonding pattern.
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Affiliation(s)
- Tobias Watermann
- Institute of Chemistry
- Martin Luther University Halle-Wittenberg
- 06120 Halle (Saale), Germany
| | - Hossam Elgabarty
- Institute of Physical Chemistry
- Johannes Gutenberg University Mainz
- 55128 Mainz, Germany
| | - Daniel Sebastiani
- Institute of Chemistry
- Martin Luther University Halle-Wittenberg
- 06120 Halle (Saale), Germany
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8
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Mizutani T, Yagi S. Linear tetrapyrroles as functional pigments in chemistry and biology. J PORPHYR PHTHALOCYA 2012. [DOI: 10.1142/s1088424604000210] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
1,19,21,24-tetrahydro-1,19-bilindione is the framework of pigments frequently found in nature, which includes biliverdin IX α, phytochromobilin and phycocyanobilin. 1,19-bilindiones have unique features such as (1) photochemical and thermal cis-trans isomerization, (2) excited energy transfer, (3) chiroptical properties due to the cyclic helical conformation, (4) redox activity, (5) coordination to various metals, and (6) reconstitution to proteins. 1,19-bilindione can adopt a number of conformations since it has exocyclic three double bonds and three single bonds that are rotatable thermally and photochemically. In solution, biliverdin and phycocyanobilin adopt a cyclic helical ZZZ, syn, syn, syn conformation, but other conformations are stabilized depending on the experimental conditions and substituents on the bilin framework. The conformational changes in 1,19-bilindiones are related to the biological functions of a photoreceptor protein, phytochrome. Structural and conformational studies of bilindiones are summarized both in solution and in protein. The conformational changes of bilins can be used for other functions such as a chirality sensor. The bilindiones and the zinc complexes of bilindiones can be employed as a chirality sensor due to the helically chiral structure and the dynamics of racemization of enantiomers. In this paper, we discuss the conformational equilibria and dynamics of bilindiones and its implications in photobiology and materials science.
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Affiliation(s)
- Tadashi Mizutani
- Department of Molecular Science and Technology, Faculty of Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321, Japan
| | - Shigeyuki Yagi
- Department of Applied Materials Science, Graduate School of Engineering, Osaka Prefecture University, Gakuen-cho, Sakai, Osaka 599-8531, Japan
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König C, Neugebauer J. Quantum chemical description of absorption properties and excited-state processes in photosynthetic systems. Chemphyschem 2011; 13:386-425. [PMID: 22287108 DOI: 10.1002/cphc.201100408] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Indexed: 11/07/2022]
Abstract
The theoretical description of the initial steps in photosynthesis has gained increasing importance over the past few years. This is caused by more and more structural data becoming available for light-harvesting complexes and reaction centers which form the basis for atomistic calculations and by the progress made in the development of first-principles methods for excited electronic states of large molecules. In this Review, we discuss the advantages and pitfalls of theoretical methods applicable to photosynthetic pigments. Besides methodological aspects of excited-state electronic-structure methods, studies on chlorophyll-type and carotenoid-like molecules are discussed. We also address the concepts of exciton coupling and excitation-energy transfer (EET) and compare the different theoretical methods for the calculation of EET coupling constants. Applications to photosynthetic light-harvesting complexes and reaction centers based on such models are also analyzed.
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Affiliation(s)
- Carolin König
- Institute for Physical and Theoretical Chemistry, Technical University Braunschweig, Braunschweig, Germany
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10
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Dietzek B, Fey S, Matute RA, González L, Schmitt M, Popp J, Yartsev A, Hermann G. Wavelength-dependent photoproduct formation of phycocyanobilin in solution – Indications for competing reaction pathways. Chem Phys Lett 2011. [DOI: 10.1016/j.cplett.2011.08.086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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11
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Rohmer T, Lang C, Gärtner W, Hughes J, Matysik J. Role of the protein cavity in phytochrome chromoprotein assembly and double-bond isomerization: a comparison with model compounds. Photochem Photobiol 2010; 86:856-61. [PMID: 20492561 DOI: 10.1111/j.1751-1097.2010.00740.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Difference patterns of (13)C NMR chemicals shifts for the protonation of a free model compound in organic solution, as reported in the literature (M. Stanek, K. Grubmayr [1998] Chem. Eur. J.4, 1653-1659), were compared with changes in the protonation state occurring during holophytochrome assembly from phycocyanobilin (PCB) and the apoprotein. Both processes induce identical changes in the NMR signals, indicating that the assembly process is linked to protonation of the chromophore, yielding a cationic cofactor in a heterogeneous, quasi-liquid protein environment. The identity of both difference patterns implies that the protonation of a model compound in solution causes a partial stretching of the geometry of the macrocycle as found in the protein. In fact, the similarity of the difference pattern within the bilin family for identical chemical transformations represents a basis for future theoretical analysis. On the other hand, the change of the (13)C NMR chemical shift pattern upon the Pr --> Pfr photoisomerization is very different to that of the free model compound upon ZZZ --> ZZE photoisomerization. Hence, the character of the double-bond isomerization in phytochrome is essentially different from that of a classical photoinduced double-bond isomerization, emphasizing the role of the protein environment in the modulation of this light-induced process.
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Affiliation(s)
- Thierry Rohmer
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
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12
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Göller AH, Strehlow D, Hermann G. The excited-state chemistry of phycocyanobilin: a semiempirical study. Chemphyschem 2007; 6:1259-68. [PMID: 15942968 DOI: 10.1002/cphc.200400667] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Based on previous time-resolved absorption studies, phycocyanobilin undergoes a photoreaction from an A- into a B- and C-form, with the latter two photoproducts showing absorption spectra red-shifted from A. To identify the molecular mechanism involved in the excited-state reactions, the structural origin of the red shift in the absorption spectra is investigated. Using semiempirical AM1 calculations that include configuration interaction by pair doubles excitation configuration interaction, the absorption spectra of different conformers as well as different protonation states were calculated. The results clearly indicate a pronounced red shift in the spectra of structures either protonated or deprotonated at the basic/acidic centres of the tetrapyrrole chromophore whereas, in contrast, conformational changes alone result in a blue shift. Furthermore, it is shown by quantum chemical calculations that the basicity of phycocyanobilin is much higher in the excited than in the ground state, with a decrease in the excited-state pK(B)* of approximately 9.5 units. The acidity is only slightly enhanced with a drop in pK(A)* of only approximately 1.6 units. From these findings, a reaction model for the excited-state processes in phycocyanobilin is proposed. According to this model, photoexcitation of phycocyanobilin triggers an excited-state proton transfer giving rise to the formation of a protonated species. In parallel, the local increase in the medium pH associated with protonation then forwards a deprotonation at an acidic NH-group so that in effect both protonated and deprotonated phycocyanobilin would arise from the initial photoreaction and account for the observed red shift in the spectra of the B- and C-forms.
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Affiliation(s)
- Andreas H Göller
- Institut für Physikalische Chemie, Friedrich-Schiller-Universität Jena, Lessingstrasse 10, 07743 Jena, Germany.
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Abstract
Phytochromes are a widespread family of red/far-red responsive photoreceptors first discovered in plants, where they constitute one of the three main classes of photomorphogenesis regulators. All phytochromes utilize covalently attached bilin chromophores that enable photoconversion between red-absorbing (P(r)) and far-red-absorbing (P(fr)) forms. Phytochromes are thus photoswitchable photosensors; canonical phytochromes have a conserved N-terminal photosensory core and a C-terminal regulatory region, which typically includes a histidine-kinase-related domain. The discovery of new bacterial and cyanobacterial members of the phytochrome family within the last decade has greatly aided biochemical and structural characterization of this family, with the first crystal structure of a bacteriophytochrome photosensory core appearing in 2005. This structure and other recent biochemical studies have provided exciting new insights into the structure of phytochrome, the photoconversion process that is central to light sensing, and the mechanism of signal transfer by this important family of photoreceptors.
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Affiliation(s)
- Nathan C. Rockwell
- Section of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Yi-Shin Su
- Section of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - J. Clark Lagarias
- Section of Molecular and Cellular Biology, University of California, Davis, CA 95616
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An ab initio conformational study on 2,3-dihydrobilin-1,19(21H,24H)-dione, a model compound for open-chain tetrapyrroles. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.theochem.2004.04.040] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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