1
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Nevonen DE, Atoyebi AO, Luciano MP, Brückner C, Nemykin VN. Electronic Structures of an Annulated meso-Tetraphenylchlorin and a Related Chlorin Analogue Incorporating an 8-Membered Ring through MCD Spectroscopy and DFT Calculations. J Phys Chem A 2024; 128:4823-4829. [PMID: 38857383 DOI: 10.1021/acs.jpca.4c02803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2024]
Abstract
Herein, we compare the electronic structures of the metal-free and nickel(II) derivatives of an annulated meso-tetraphenyldihydroxychlorin with those of the (metallo)chlorin analogues derived by pyrroline β,β'-ring cleavage of the annulated (metallo)chlorins. These (metallo)chlorin analogues incorporate 8-membered heterocycles in place of the pyrroline, carry oxo-functionalities on the former pyrroline β-carbon atoms, and were previously shown to possess drastically ruffled (twisted) nonplanar conformations. The magnetic circular dichroism spectra of all chromophores investigated feature chlorin-like UV-vis spectra and correspondingly reversed (positive-to-negative in ascending energy) sign sequences in the Q-band region, indicative of ΔHOMO < ΔLUMO relationships. Density functional theory (DFT) calculations indicate that the HOMOs in all compounds are a1u-type molecular orbitals (in traditional for the porphyrin spectroscopy D4h point group). Time-dependent DFT calculations correlate well with the experimental spectra and indicate that Gouterman's four-orbital model can be applied to these chromophores. This work highlights to which degree synthetic chlorin analogues can deviate from the structural parameters of natural chlorins without losing their electronic chlorin characteristics.
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Affiliation(s)
- Dustin E Nevonen
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Adewole O Atoyebi
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Michael P Luciano
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Christian Brückner
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Victor N Nemykin
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
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2
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Nguyen KU, Zhang Y, Liu Q, Zhang R, Jin X, Taniguchi M, Miller ES, Lindsey JS. Tolyporphins-Exotic Tetrapyrrole Pigments in a Cyanobacterium-A Review. Molecules 2023; 28:6132. [PMID: 37630384 PMCID: PMC10459692 DOI: 10.3390/molecules28166132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 08/11/2023] [Accepted: 08/13/2023] [Indexed: 08/27/2023] Open
Abstract
Tolyporphins were discovered some 30 years ago as part of a global search for antineoplastic compounds from cyanobacteria. To date, the culture HT-58-2, comprised of a cyanobacterium-microbial consortium, is the sole known producer of tolyporphins. Eighteen tolyporphins are now known-each is a free base tetrapyrrole macrocycle with a dioxobacteriochlorin (14), oxochlorin (3), or porphyrin (1) chromophore. Each compound displays two, three, or four open β-pyrrole positions and two, one, or zero appended C-glycoside (or -OH or -OAc) groups, respectively; the appended groups form part of a geminal disubstitution motif flanking the oxo moiety in the pyrroline ring. The distinct structures and repertoire of tolyporphins stand alone in the large pigments-of-life family. Efforts to understand the cyanobacterial origin, biosynthetic pathways, structural diversity, physiological roles, and potential pharmacological properties of tolyporphins have attracted a broad spectrum of researchers from diverse scientific areas. The identification of putative biosynthetic gene clusters in the HT-58-2 cyanobacterial genome and accompanying studies suggest a new biosynthetic paradigm in the tetrapyrrole arena. The present review provides a comprehensive treatment of the rich science concerning tolyporphins.
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Affiliation(s)
- Kathy-Uyen Nguyen
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA; (K.-U.N.); (Y.Z.); (Q.L.); (R.Z.); (X.J.); (M.T.)
| | - Yunlong Zhang
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA; (K.-U.N.); (Y.Z.); (Q.L.); (R.Z.); (X.J.); (M.T.)
| | - Qihui Liu
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA; (K.-U.N.); (Y.Z.); (Q.L.); (R.Z.); (X.J.); (M.T.)
| | - Ran Zhang
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA; (K.-U.N.); (Y.Z.); (Q.L.); (R.Z.); (X.J.); (M.T.)
| | - Xiaohe Jin
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA; (K.-U.N.); (Y.Z.); (Q.L.); (R.Z.); (X.J.); (M.T.)
| | - Masahiko Taniguchi
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA; (K.-U.N.); (Y.Z.); (Q.L.); (R.Z.); (X.J.); (M.T.)
| | - Eric S. Miller
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695-7612, USA;
| | - Jonathan S. Lindsey
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204, USA; (K.-U.N.); (Y.Z.); (Q.L.); (R.Z.); (X.J.); (M.T.)
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3
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Hewage N, Guberman-Pfeffer MJ, Chaudhri N, Zeller M, Gascón JA, Brückner C. Syntheses and Aromaticity Parameters of Hexahydroxypyrrocorphin, Porphotrilactones, and Their Oxidation State Intermediates. J Org Chem 2022; 87:12096-12108. [PMID: 36066858 DOI: 10.1021/acs.joc.2c01202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Triple OsO4-mediated dihydroxylation of meso-tetrakis(pentafluorophenyl)porphyrin formed a non-aromatic hexahydroxypyrrocorphin as a single stereo-isomer. A one-step oxidative conversion of all three diol functionalities to lactone moieties generated three out of the four possible porphotrilactone regioisomers that were spectroscopically and structurally characterized. This conversion recovered most of the porphyrinic macrocycle aromatic ring current, as seen in their 1H NMR spectra and modeled using DFT computations. Stepwise OsO4-mediated dihydroxylations of porpho-mono- and -di-lactones generated intermediate oxidation state compounds between the pyrrole-three pyrroline macrocycle of the pyrrocorphin and the pyrrole-three oxazolone chromophore of the trilactones. The aromaticity of these chromophores was reduced with increasing number of oxazolone to pyrroline replacements, showing the importance for the presence of three lactone moieties for the retention of the macrocycle aromaticity in the tris-β,β'-modified macrocycles. This work first describes hexahydoxypyrrocorphins, porphotrislactones, and the oxidation state intermediates between them; furthers the understanding of the roles of β-lactone moieties in the expression of porphyrinic macrocycle aromaticity; and generally broadens access to chemically stable pyrrocorphins and pyrrocorphin analogues.
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Affiliation(s)
- Nisansala Hewage
- Department of Chemistry, University of Connecticut, Unit 3060, Storrs, Connecticut 06269-3060, United States
| | - Matthew J Guberman-Pfeffer
- Department of Chemistry, University of Connecticut, Unit 3060, Storrs, Connecticut 06269-3060, United States
| | - Nivedita Chaudhri
- Department of Chemistry, University of Connecticut, Unit 3060, Storrs, Connecticut 06269-3060, United States
| | - Matthias Zeller
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084, United States
| | - José A Gascón
- Department of Chemistry, University of Connecticut, Unit 3060, Storrs, Connecticut 06269-3060, United States
| | - Christian Brückner
- Department of Chemistry, University of Connecticut, Unit 3060, Storrs, Connecticut 06269-3060, United States
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4
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Bhattacharya S, Graf A, Gomes AKM, Chaudhri N, Chekulaev D, Brückner C, Cardozo TM, Chauvet AAP. Tailoring the Intersystem Crossing and Triplet Dynamics of Free-Base Octaalkyl-β-oxo-Substituted Porphyrins: Competing Effects of Spin-Vibronic and NH Tautomerism Relaxation Channels. J Phys Chem A 2022; 126:2522-2531. [PMID: 35348324 PMCID: PMC9059185 DOI: 10.1021/acs.jpca.2c01225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 03/16/2022] [Indexed: 11/30/2022]
Abstract
We demonstrate that β-oxo-substitution provides effective fine-tuning of both steady-state and transient electronic properties of octaalkyl-β-mono-oxochlorin and all isomers of the β,β'-dioxo-substituted chromophores. The addition of a carbonyl group increases the Qy oscillator strength and red-shifts the absorption spectra. Each oxo-substitution results in a 2-fold increase in the singlet to triplet state intersystem crossing (ISC) rates, resulting in a 4-fold ISC rate increase for the dioxo-substituted chromophores. The effects of oxo-substitution on the ISC rate are thus additive. The progressive increase in the ISC rates correlates directly with the spin-vibronic channels provided by the C═O out-of-plane distortion modes, as evidenced by density functional theory (DFT) modeling. The triplet states, however, were not evenly affected by β-oxo-substitution, and reduction in the triplet lifetime seems to be influenced instead by the presence of NH tautomers in the dioxoisobacteriochlorins.
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Affiliation(s)
- Sayantan Bhattacharya
- Department
of Chemistry, The University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - Arthur Graf
- Department
of Chemistry, The University of Sheffield, Sheffield S3 7HF, United Kingdom
| | | | - Nivedita Chaudhri
- Department
of Chemistry, University of Connecticut, Storrs, Connecticut 06269-3060, United States
| | - Dimitri Chekulaev
- Department
of Chemistry, The University of Sheffield, Sheffield S3 7HF, United Kingdom
| | - Christian Brückner
- Department
of Chemistry, University of Connecticut, Storrs, Connecticut 06269-3060, United States
| | - Thiago M. Cardozo
- Instituto
de Química (IQ), Federal University
of Rio de Janeiro, Rio de
Janeiro 21941-909, Brazil
| | - Adrien A. P. Chauvet
- Department
of Chemistry, The University of Sheffield, Sheffield S3 7HF, United Kingdom
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5
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Jing H, Wang P, Chen B, Jiang J, Vairaprakash P, Liu S, Rong J, Chen CY, Nalaoh P, Lindsey JS. Synthesis of bacteriochlorins bearing diverse β-substituents. NEW J CHEM 2022. [DOI: 10.1039/d1nj05852e] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Eleven bacteriochlorins have been prepared for surface attachment, bioconjugation, water-solubilization, vibrational studies, and elaboration into multichromophore arrays.
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Affiliation(s)
- Haoyu Jing
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Pengzhi Wang
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Boyang Chen
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Jianbing Jiang
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Pothiappan Vairaprakash
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Sijia Liu
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Jie Rong
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Chih-Yuan Chen
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Phattananawee Nalaoh
- Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong, 21210, Thailand
| | - Jonathan S. Lindsey
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
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6
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Brückner C, Chaudhri N, Nevonen DE, Bhattacharya S, Graf A, Kaesmann E, Li R, Guberman-Pfeffer MJ, Mani T, Nimthong-Roldán A, Zeller M, Chauvet AAP, Nemykin V. Structural and Photophysical Characterization of All Five Constitutional Isomers of the Octaethyl-β,β'-dioxo-bacterio- and -isobacteriochlorin Series. Chemistry 2021; 27:16189-16203. [PMID: 34535932 DOI: 10.1002/chem.202103014] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Indexed: 11/11/2022]
Abstract
It is well-known that treatment of β-octaethylporphyrin with H2 O2 /conc. H2 SO4 converts it to a β-oxochlorin as well as all five constitutional isomers of the corresponding β,β'-dioxo-derivatives: two bacteriochlorin-type isomers (β-oxo groups at opposite pyrrolic building blocks) and three isobacteriochlorin-type isomers (β-oxo-groups at adjacent pyrrolic building blocks). By virtue of the presence of the strongly electronically coupled β-oxo auxochromes, none of the chromophores are archetypical chlorins, bacteriochlorins, or isobacteriochlorins. Here the authors present, inter alia, the single crystal X-ray structures of all free-base diketone isomers and a comparative description of their UV-vis absorption spectra in neutral and acidic solutions, and fluorescence emission and singlet oxygen photosensitization properties, Magnetic Circular Dichroism (MCD) spectra, and singlet excited state lifetimes. DFT computations uncover underlying tautomeric equilibria and electronic interactions controlling their electronic properties, adding to the understanding of porphyrinoids carrying β-oxo functionalities. This comparative study lays the basis for their further study and utilization.
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Affiliation(s)
- Christian Brückner
- Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060, United States
| | - Nivedita Chaudhri
- Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060, United States
| | - Dustin E Nevonen
- Department of Chemistry, University of Manitoba Winnipeg, Manitoba, R3T 2 N2, Canada
| | - Sayantan Bhattacharya
- Department of Chemistry, University of Sheffield Dainton Building, Sheffield, S3 7HF, United Kingdom
| | - Arthur Graf
- Department of Chemistry, University of Sheffield Dainton Building, Sheffield, S3 7HF, United Kingdom
| | - Elizabeth Kaesmann
- Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060, United States
| | - Ruoshi Li
- Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060, United States
| | | | - Tomoyasu Mani
- Department of Chemistry, University of Connecticut, Storrs, CT 06269-3060, United States
| | - Arunpatcha Nimthong-Roldán
- Department of Chemistry, Youngstown State University One University Plaza, Youngstown, OH 44555-3663, United States
| | - Matthias Zeller
- Department of Chemistry, Youngstown State University One University Plaza, Youngstown, OH 44555-3663, United States.,Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907-2084, United States
| | - Adrien A P Chauvet
- Department of Chemistry, University of Sheffield Dainton Building, Sheffield, S3 7HF, United Kingdom
| | - Victor Nemykin
- Department of Chemistry, University of Manitoba Winnipeg, Manitoba, R3T 2 N2, Canada.,Department of Chemistry, University of Tennessee, 552 Buehler Hall, 1420 Circle Dr., Knoxville, TN, 37996-1600, United States
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7
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Sollert C, Kocsi D, Jane RT, Orthaber A, Borbas KE. C-glycosylated pyrroles and their application in dipyrromethane and porphyrin synthesis. J PORPHYR PHTHALOCYA 2021. [DOI: 10.1142/s1088424621500723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Pyrrole C-glycosylated in either the 2- or the 3-position could be prepared by the acid-catalyzed reaction between trichloroacetimidate glycosyl donors and pyrrole, or [Formula: see text]-phenyl-tri?uoroacetimidate glucosyl donor and [Formula: see text]-TIPS pyrrole, respectively. Pyrroles carrying glucose, mannose, galactose and lactose in the 2-position, and glucose in the 3-position were obtained. The configurations of the products could be assigned using a combination of 1D and 2D NMR spectroscopy. A number of undesired background reactions yielding a variety of stereo- and regioisomers were identified; in several cases these could be eliminated. Glycosylpyrroles could be incorporated into mono- and diglycosylated dipyrromethanes, a diglycosylated BODIPY dye, and a monoglycosylated Zn(II) porphyrin without damaging the sugar unit.
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Affiliation(s)
- Carina Sollert
- Department of Chemistry, Ångström Laboratory, Box 523, Uppsala University, 75120 Uppsala, Sweden
| | - Daniel Kocsi
- Department of Chemistry, Ångström Laboratory, Box 523, Uppsala University, 75120 Uppsala, Sweden
| | - Reuben T. Jane
- Department of Chemistry, Ångström Laboratory, Box 523, Uppsala University, 75120 Uppsala, Sweden
| | - Andreas Orthaber
- Department of Chemistry, Ångström Laboratory, Box 523, Uppsala University, 75120 Uppsala, Sweden
| | - K. Eszter Borbas
- Department of Chemistry, Ångström Laboratory, Box 523, Uppsala University, 75120 Uppsala, Sweden
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8
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Nguyen KU, Zhang R, Taniguchi M, Lindsey JS. Fluorescence Assay for Tolyporphins Amidst Abundant Chlorophyll in Crude Cyanobacterial Extracts. Photochem Photobiol 2021; 97:1507-1515. [PMID: 34152600 DOI: 10.1111/php.13474] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 06/17/2021] [Indexed: 11/30/2022]
Abstract
Tolyporphins are distinctive tetrapyrrole natural products found singularly in a filamentous cyanobacterial-microbial holobiont (termed HT-58-2) from Micronesia. The absorption and fluorescence features of tolyporphins resemble those of chlorophyll a, complicating direct analysis of culture samples. Treatment of the crude (unfractionated) organic extract (CH2 Cl2 /2-propanol, 1:1) of HT-58-2 cultures with NaBH4 in methanol causes reduction of the peripheral ketone auxochromes, whereupon tolyporphins (predominantly 7,17-dioxobacteriochlorins) exhibit a bathochromic shift (λabs ~ 676 → ~ 700 nm) and chlorophyll a (a 131 -oxochlorin) exhibits a hypsochromic shift (λabs 665 → 634 nm). Fluorescence excitation spectroscopy (at 368 and 491 nm with λem 710 nm) enabled detection of reduced tolyporphins amidst abundant reduced chlorophyll a (1:19 ratio), a detection sensitivity >5 times that without reduction. The resulting assay combines simple sample preparation from non-axenic cultures at microscale quantities (2 mL, 2 μm), absence of any fractionation procedures, and fluorescence detection. Tolyporphins were readily detected in cultures of HT-58-2 at reasonable growth periods in the absence of environmental stressors, which was not possible previously.
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Affiliation(s)
- Kathy-Uyen Nguyen
- Department of Chemistry, North Carolina State University, Raleigh, NC
| | - Ran Zhang
- Department of Chemistry, North Carolina State University, Raleigh, NC
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9
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O'Donnell TJ, Gurr JR, Dai J, Taniguchi M, Williams PG, Lindsey JS. Tolyporphins A–R, unusual tetrapyrrole macrocycles in a cyanobacterium from Micronesia, assessed quantitatively from the culture HT-58-2. NEW J CHEM 2021. [DOI: 10.1039/d1nj02108g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Tolyporphins A–R are the newest additions to the family of native tetrapyrroles. LC-MS-dMRM and absorption spectroscopy have been employed for analysis of mixtures containing the 18 distinctive natural products.
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Affiliation(s)
| | - Joshua R. Gurr
- Department of Chemistry
- University of Hawaii at Manoa
- Honolulu
- USA
| | - Jingqiu Dai
- Department of Chemistry
- University of Hawaii at Manoa
- Honolulu
- USA
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10
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Chung DTM, Tran PV, Chau Nguyen K, Wang P, Lindsey JS. Synthesis of model bacteriochlorophylls containing substituents of native rings A, C and E. NEW J CHEM 2021. [DOI: 10.1039/d1nj02469h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
An established route to the bacteriochlorophyll skeleton from two dihydrodipyrrin halves has been extended to accommodate several substituents characteristic of the native bacteriochlorophyll a.
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Affiliation(s)
- Duy T. M. Chung
- Department of Chemistry
- North Carolina State University
- Raleigh
- USA
| | - Phuong Vy Tran
- Department of Chemistry
- North Carolina State University
- Raleigh
- USA
| | | | - Pengzhi Wang
- Department of Chemistry
- North Carolina State University
- Raleigh
- USA
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11
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Abstract
Tolyporphins, relatively new members of the pigments of life family found in a cyanobacterium, differ in the chromophores, pyrroline substituents, and stereochemistry, yet likely all derive from uroporphyrinogen III.
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12
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Chaudhri N, Zeller M, Brückner C. Stepwise Reduction of Octaethyl-β,β'-dioxochlorin Isomers: Access to Structurally and Electronically Diverse Hydroporphyrins. J Org Chem 2020; 85:13951-13964. [PMID: 33085480 DOI: 10.1021/acs.joc.0c01989] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Di- and tetrahydroporphyrins (chlorins, bacteriochlorins and isobacteriochlorins, respectively) are key "pigments of life." They have been a major focus of attention in synthetic tetrapyrrole chemistry. A long-known one-pot epoxidation/epoxide ring-opening/pinacol-pinacolone rearrangement of octaethylporphyrin (OEP) generates a β-ketochlorin and all five β,β'-diketone isomers. We present herein the single and double reductions of all isomers of the β,β'-diketones, generating hydroxychlorin and β-hydroxy-β-ketodihydroporphyrin isomers, generally in regioselective manner, and sets of separable stereoisomeric dihydroxytetrahydroporphyrin regioisomers. The connectivity of the regio- and stereoisomers were determined spectroscopically and, in many cases, using single-crystal X-ray crystallography. The optical properties of the chlorin-, bacteriochlorin-, and isobacteriochlorin-type chromophores are described. They highlight general observations on the regiochemical effects of the β-oxo-auxochrome. This contribution thus delineates the formation of a range of regio- and stereoisomers of a family of chromophores with broadly varying optical properties from a single and readily available starting material (OEP) in two straightforward steps, albeit requiring extensive chromatography.
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Affiliation(s)
- Nivedita Chaudhri
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269-3060, United States
| | - Matthias Zeller
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084, United States
| | - Christian Brückner
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269-3060, United States
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13
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Schnable D, Chaudhri N, Li R, Zeller M, Brückner C. Evaluation of Octaethyl-7,17-dioxobacteriochlorin as a Ligand for Transition Metals. Inorg Chem 2020; 59:2870-2880. [DOI: 10.1021/acs.inorgchem.9b03231] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- David Schnable
- Department of Chemistry, Unit 3060, University of Connecticut, Storrs, Connecticut 06269-3060, United States
| | - Nivedita Chaudhri
- Department of Chemistry, Unit 3060, University of Connecticut, Storrs, Connecticut 06269-3060, United States
| | - Ruoshi Li
- Department of Chemistry, Unit 3060, University of Connecticut, Storrs, Connecticut 06269-3060, United States
| | - Matthias Zeller
- Department of Chemistry, Purdue University, 101 Wetherill Hall, 560 Oval Drive, West Lafayette, Indiana 47907-2084, United States
| | - Christian Brückner
- Department of Chemistry, Unit 3060, University of Connecticut, Storrs, Connecticut 06269-3060, United States
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14
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Gurr JR, Dai J, Philbin CS, Sartain HT, O'Donnell TJ, Yoshida WY, Rheingold AL, Williams PG. Tolyporphins L-R: Unusual Tetrapyrroles from a Brasilonema sp. of Cyanobacterium. J Org Chem 2019; 85:318-326. [PMID: 31815480 DOI: 10.1021/acs.joc.9b01928] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Tolyporphins L-R (2-8) have been isolated from a mixed cyanobacterium-microbial culture. The structures of tolyporphins L and M have been revised to four constitutional isomers, isolated as two mixtures of dioxobacteriochlorins (2/3 and 4/5). In contrast, tolyporphin P (6) is a fully oxidized tetrapyrrole, while tolyporphins Q and R (7 and 8) are oxochlorins. X-ray structures are reported for the first time for tolyporphins A (1), R (8), and E (9), revealing unexpected stereochemical variation within the series.
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Affiliation(s)
- Joshua R Gurr
- Department of Chemistry , University of Hawaii at Manoa , Honolulu , Hawaii 96822 , United States
| | - Jingqiu Dai
- Department of Chemistry , University of Hawaii at Manoa , Honolulu , Hawaii 96822 , United States
| | - Casey S Philbin
- Department of Chemistry , University of Hawaii at Manoa , Honolulu , Hawaii 96822 , United States
| | - Hope T Sartain
- Department of Chemistry , University of Hawaii at Manoa , Honolulu , Hawaii 96822 , United States
| | - Timothy J O'Donnell
- Department of Chemistry , University of Hawaii at Manoa , Honolulu , Hawaii 96822 , United States
| | - Wesley Y Yoshida
- Department of Chemistry , University of Hawaii at Manoa , Honolulu , Hawaii 96822 , United States
| | - Arnold L Rheingold
- Department of Chemistry , University of California, San Diego , 9500 Gilman Drive , La Jolla , 92093 California , United States
| | - Philip G Williams
- Department of Chemistry , University of Hawaii at Manoa , Honolulu , Hawaii 96822 , United States
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Barnhart-Dailey M, Zhang Y, Zhang R, Anthony SM, Aaron JS, Miller ES, Lindsey JS, Timlin JA. Cellular localization of tolyporphins, unusual tetrapyrroles, in a microbial photosynthetic community determined using hyperspectral confocal fluorescence microscopy. PHOTOSYNTHESIS RESEARCH 2019; 141:259-271. [PMID: 30903482 DOI: 10.1007/s11120-019-00625-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 11/26/2018] [Indexed: 06/09/2023]
Abstract
The cyanobacterial culture HT-58-2, composed of a filamentous cyanobacterium and accompanying community bacteria, produces chlorophyll a as well as the tetrapyrrole macrocycles known as tolyporphins. Almost all known tolyporphins (A-M except K) contain a dioxobacteriochlorin chromophore and exhibit an absorption spectrum somewhat similar to that of chlorophyll a. Here, hyperspectral confocal fluorescence microscopy was employed to noninvasively probe the locale of tolyporphins within live cells under various growth conditions (media, illumination, culture age). Cultures grown in nitrate-depleted media (BG-110 vs. nitrate-rich, BG-11) are known to increase the production of tolyporphins by orders of magnitude (rivaling that of chlorophyll a) over a period of 30-45 days. Multivariate curve resolution (MCR) was applied to an image set containing images from each condition to obtain pure component spectra of the endogenous pigments. The relative abundances of these components were then calculated for individual pixels in each image in the entire set, and 3D-volume renderings were obtained. At 30 days in media with or without nitrate, the chlorophyll a and phycobilisomes (combined phycocyanin and phycobilin components) co-localize in the filament outer cytoplasmic region. Tolyporphins localize in a distinct peripheral pattern in cells grown in BG-110 versus a diffuse pattern (mimicking the chlorophyll a localization) upon growth in BG-11. In BG-110, distinct puncta of tolyporphins were commonly found at the septa between cells and at the end of filaments. This work quantifies the relative abundance and envelope localization of tolyporphins in single cells, and illustrates the ability to identify novel tetrapyrroles in the presence of chlorophyll a in a photosynthetic microorganism within a non-axenic culture.
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Affiliation(s)
- Meghan Barnhart-Dailey
- Bioenergy and Defense Technologies, Sandia National Laboratories, Albuquerque, NM, 87185-0895, USA
| | - Yunlong Zhang
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695-8204, USA
| | - Ran Zhang
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695-8204, USA
| | - Stephen M Anthony
- Bioenergy and Defense Technologies, Sandia National Laboratories, Albuquerque, NM, 87185-0895, USA
| | - Jesse S Aaron
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, 20147, USA
| | - Eric S Miller
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695-7615, USA
| | - Jonathan S Lindsey
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695-8204, USA.
| | - Jerilyn A Timlin
- Bioenergy and Defense Technologies, Sandia National Laboratories, Albuquerque, NM, 87185-0895, USA.
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Guberman-Pfeffer MJ, Lalisse RF, Hewage N, Brückner C, Gascón JA. Origins of the Electronic Modulations of Bacterio- and Isobacteriodilactone Regioisomers. J Phys Chem A 2019; 123:7470-7485. [PMID: 31361130 DOI: 10.1021/acs.jpca.9b05656] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Advances in the utilization of porphyrinoids for photomedicine, catalysis, and artificial photosynthesis require a fundamental understanding of the relationships between their molecular connectivity and resulting electronic structures. Herein, we analyze how the replacement of two pyrrolic Cβ═Cβ bonds of a porphyrin by two lactone (O═C-O) moieties modulates the ground-state thermodynamic stability and electronic structure of the resulting five possible pyrrole-modified porphyrin isomers. We made these determinations based on density functional theory (DFT) and time-dependent DFT computations of the optical spectra of all regioisomers. We also analyzed the computed magnetically induced currents of their aromatic π-systems. All regioisomers adopt the tautomeric state that maximizes aromaticity, whether or not transannular steric strains are incurred. In all isomers, the O═Cβ-Oβ bonds were found to support a macrocycle diatropic ring current. We attributed this to the delocalization of nonbonding electrons from the ring oxa- and oxo-atoms into the macrocycle. As a consequence of this delocalization, the dilactone regioisomers are as-or even more-aromatic than their hydroporphyrin congeners. The electronic structures follow different trends for the bacteriochlorin- and isobacteriochlorin-type isomers. The presence of either oxo- or oxa-oxygens conjugated with the macrocyclic π-system was found to be the minimal structural requirement for the regioisomers to exhibit distinct electronic properties. Our computational methods and mechanistic insights provide a basis for the systematic exploration of the physicochemical properties of porphyrinoids as a function of the number, relative orientation, and degree of macrocycle-π-conjugation of β-substituents, in general, and for dilactone-based porphyrinic chromophores, in particular.
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Affiliation(s)
- Matthew J Guberman-Pfeffer
- Department of Chemistry , University of Connecticut , Unit 3060 , Storrs , Connecticut 06269-3060 , United States
| | - Remy F Lalisse
- Department of Chemistry , University of Connecticut , Unit 3060 , Storrs , Connecticut 06269-3060 , United States
| | - Nisansala Hewage
- Department of Chemistry , University of Connecticut , Unit 3060 , Storrs , Connecticut 06269-3060 , United States
| | - Christian Brückner
- Department of Chemistry , University of Connecticut , Unit 3060 , Storrs , Connecticut 06269-3060 , United States
| | - José A Gascón
- Department of Chemistry , University of Connecticut , Unit 3060 , Storrs , Connecticut 06269-3060 , United States
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Liu Y, Zhang S, Lindsey JS. Total synthesis campaigns toward chlorophylls and related natural hydroporphyrins - diverse macrocycles, unrealized opportunities. Nat Prod Rep 2019; 35:879-901. [PMID: 29845995 DOI: 10.1039/c8np00020d] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Covering: up to 2018 Chlorophylls, bacteriochlorophylls and related hydroporphyrins constitute invaluable natural products but have largely remained outside the scope of viable syntheses. The campaign toward chlorophyll a by Woodward and coworkers is a deservedly celebrated landmark in organic synthesis yet the route entailed 49 steps, relied on semisynthetic replenishment of advanced intermediates, and then pointed to (but did not implement) uncertain literature procedures for the final transformations. Indeed, the full synthesis at any scale of any (bacterio)chlorophylls - conversion of small-molecule starting materials to the product - has never been accomplished. Herein, the reported syntheses of (±)-bonellin dimethyl ester (0.93 mg) and tolyporphin A O,O-diacetate (0.38 mg), as well as the never-fully traversed route to chlorophyll a, have been evaluated in a quantitative manner. Bonellin and tolyporphin A are naturally occurring chlorin and bacteriochlorin macrocycles, respectively, that lack the characteristic fifth ring of (bacterio)chlorophylls. A practical assessment is provided by the cumulative reaction mass efficiency (cRME) of the entire synthetic process. The cRME for the route to chlorophyll a would be 4.3 × 10-9 (230 kg of all reactants and reagents in total would yield 1.0 mg of chlorophyll a), whereas that for (±)-bonellin dimethyl ester or tolyporphin A O,O-diacetate is approximately 6.4 × 10-4 or 3.6 × 10-5, respectively. Comparison of the three syntheses reveals insights for designing hydroporphyrin syntheses. Development of syntheses with cRME > 10-5 (if not 10-4), as required to obtain 10 mg quantities of hydroporphyrin for diverse physicochemical, biochemical and medicinal chemistry studies, necessitates significant further advances in tetrapyrrole chemistry.
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Affiliation(s)
- Yizhou Liu
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8294, USA.
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Hughes RA, Jin X, Zhang Y, Zhang R, Tran S, Williams PG, Lindsey JS, Miller ES. Genome sequence, metabolic properties and cyanobacterial attachment of Porphyrobacter sp. HT-58-2 isolated from a filamentous cyanobacterium–microbial consortium. Microbiology (Reading) 2018; 164:1229-1239. [DOI: 10.1099/mic.0.000706] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Rebecca-Ayme Hughes
- 1Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
- 2Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695-7615, USA
| | - Xiaohe Jin
- 1Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Yunlong Zhang
- 1Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Ran Zhang
- 1Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Sabrina Tran
- 1Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
- 3Enloe Magnet High School, Raleigh, North Carolina 27610, USA
| | - Philip G. Williams
- 4Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822-2275, USA
| | - Jonathan S. Lindsey
- 1Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Eric S. Miller
- 2Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695-7615, USA
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Zhang Y, Zhang R, Hughes RA, Dai J, Gurr JR, Williams PG, Miller ES, Lindsey JS. Quantitation of Tolyporphins, Diverse Tetrapyrrole Secondary Metabolites with Chlorophyll-Like Absorption, from a Filamentous Cyanobacterium-Microbial Community. PHYTOCHEMICAL ANALYSIS : PCA 2018; 29:205-216. [PMID: 29110356 DOI: 10.1002/pca.2735] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 09/07/2017] [Accepted: 09/14/2017] [Indexed: 06/07/2023]
Abstract
INTRODUCTION Tolyporphins are unusual tetrapyrrole macrocycles produced by a non-axenic filamentous cyanobacterium (HT-58-2). Tolyporphins A-J, L, and M share a common dioxobacteriochlorin core, differ in peripheral substituents, and exhibit absorption spectra that overlap that of the dominant cyanobacterial pigment, chlorophyll a. Identification and accurate quantitation of the various tolyporphins in these chlorophyll-rich samples presents challenges. OBJECTIVE To develop methods for the quantitative determination of tolyporphins produced under various growth conditions relative to that of chlorophyll a. METHODOLOGY Chromatographic fractionation of large-scale (440 L) cultures afforded isolated individual tolyporphins. Lipophilic extraction of small-scale (25 mL) cultures, HPLC separation with an internal standard, and absorption detection enabled quantitation of tolyporphin A and chlorophyll a, and by inference the amounts of tolyporphins A-M. Absorption spectroscopy with multicomponent analysis of lipophilic extracts (2 mL cultures) afforded the ratio of all tolyporphins to chlorophyll a. The reported absorption spectral data for the various tolyporphins required re-evaluation for quantitative purposes. RESULTS AND DISCUSSION The amount of tolyporphin A after 50 days of illumination ranged from 0.13 nmol/mg dry cells (media containing nitrate) to 1.12 nmol/mg (without nitrate), with maximum 0.23 times that of chlorophyll a. Under soluble-nitrogen deprivation after 35-50 days, tolyporphin A represents 1/3-1/2 of the total tolyporphins, and the total amount of tolyporphins is up to 1.8-fold that of chlorophyll a. CONCLUSIONS The quantitative methods developed herein should facilitate investigation of the biosynthesis of tolyporphins (and other tetrapyrroles) as well as examination of other strains for production of tolyporphins. Copyright © 2017 John Wiley & Sons, Ltd.
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Affiliation(s)
- Yunlong Zhang
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695-8204, USA
| | - Ran Zhang
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695-8204, USA
| | - Rebecca-Ayme Hughes
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695-8204, USA
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695-8204, USA
| | - Jingqiu Dai
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI, 96822-2275, USA
| | - Joshua R Gurr
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI, 96822-2275, USA
| | - Philip G Williams
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, HI, 96822-2275, USA
| | - Eric S Miller
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, 27695-8204, USA
| | - Jonathan S Lindsey
- Department of Chemistry, North Carolina State University, Raleigh, NC, 27695-8204, USA
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Zhang Y, Zhang R, Nazari M, Bagley MC, Miller ES, Williams PG, Muddiman DC, Lindsey JS. Mass spectrometric detection of chlorophyll a and the tetrapyrrole secondary metabolite tolyporphin A in the filamentous cyanobacterium HT-58-2. Approaches to high-throughput screening of intact cyanobacteria. J PORPHYR PHTHALOCYA 2018. [DOI: 10.1142/s108842461750078x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Tolyporphins are unusual tetrapyrrole macrocycles produced by the filamentous cyanobacterium–microbial community HT-58-2, the only known source to date. Numerous cyanobacterial samples have been collected worldwide but most have not been screened for secondary metabolites. Identification of tolyporphins typically has entailed lipophilic extraction followed by chromatographic fractionation and spectroscopic and/or mass spectrometric analysis. For quantitation, lengthy lipophilic extraction, sample processing and HPLC separation are needed. Examination by MALDI-TOF-MS (with the matrix 1,5-diaminonaphthalene) of lipophilic crude extracts of small-scale HT-58-2 samples (2 mL) without chromatographic fractionation enabled semi-quantitation of tolyporphin A over a 41-day growth period. Screening for tolyporphin A in intact or slightly sheared and vortexed HT-58-2 samples (no lipophilic extraction), and confirmation of identity by tandem MS, were carried out by IR-MALDESI-FTMS. Tolyporphin A was identified by the molecular ion and four characteristic fragments. The molecular ion of chlorophyll [Formula: see text] also was observed. The sheared and vortexed sample contained substantial numbers of intact cells as demonstrated by regrowth of the filamentous cyanobacterium–microbial culture. The semi-quantitative and rapid qualitative methods developed herein should facilitate examination of other tolyporphin-producing organisms among the vast worldwide strains of cyanobacteria as well as investigation of the biosynthesis of tolyporphins.
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Affiliation(s)
- Yunlong Zhang
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Ran Zhang
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Milad Nazari
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Michael C. Bagley
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Eric S. Miller
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Philip G. Williams
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822-2275, USA
| | - David C. Muddiman
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
| | - Jonathan S. Lindsey
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA
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Genome Sequence and Composition of a Tolyporphin-Producing Cyanobacterium-Microbial Community. Appl Environ Microbiol 2017; 83:AEM.01068-17. [PMID: 28754701 DOI: 10.1128/aem.01068-17] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 07/19/2017] [Indexed: 11/20/2022] Open
Abstract
The cyanobacterial culture HT-58-2 was originally described as a strain of Tolypothrix nodosa with the ability to produce tolyporphins, which comprise a family of distinct tetrapyrrole macrocycles with reported efflux pump inhibition properties. Upon reviving the culture from what was thought to be a nonextant collection, studies of culture conditions, strain characterization, phylogeny, and genomics have been undertaken. Here, HT-58-2 was shown by 16S rRNA analysis to closely align with Brasilonema strains and not with Tolypothrix isolates. Light, fluorescence, and scanning electron microscopy revealed cyanobacterium filaments that are decorated with attached bacteria and associated with free bacteria. Metagenomic surveys of HT-58-2 cultures revealed a diversity of bacteria dominated by Erythrobacteraceae, 97% of which are Porphyrobacter species. A dimethyl sulfoxide washing procedure was found to yield enriched cyanobacterial DNA (presumably by removing community bacteria) and sequence data sufficient for genome assembly. The finished, closed HT-58-2Cyano genome consists of 7.85 Mbp (42.6% G+C) and contains 6,581 genes. All genes for biosynthesis of tetrapyrroles (e.g., heme, chlorophyll a, and phycocyanobilin) and almost all for cobalamin were identified dispersed throughout the chromosome. Among the 6,177 protein-encoding genes, coding sequences (CDSs) for all but two of the eight enzymes for conversion of glutamic acid to protoporphyrinogen IX also were found within one major gene cluster. The cluster also includes 10 putative genes (and one hypothetical gene) encoding proteins with domains for a glycosyltransferase, two cytochrome P450 enzymes, and a flavin adenine dinucleotide (FAD)-binding protein. The composition of the gene cluster suggests a possible role in tolyporphin biosynthesis.IMPORTANCE A worldwide search more than 25 years ago for cyanobacterial natural products with anticancer activity identified a culture (HT-58-2) from Micronesia that produces tolyporphins. Tolyporphins are tetrapyrroles, like chlorophylls, but have several profound structural differences that reside outside the bounds of known biosynthetic pathways. To begin probing the biosynthetic origin and biological function of tolyporphins, our research has focused on studying the cyanobacterial strain, about which almost nothing has been previously reported. We find that the HT-58-2 culture is composed of the cyanobacterium and a community of associated bacteria, complicating the question of which organisms make tolyporphins. Elucidation of the cyanobacterial genome revealed an intriguing gene cluster that contains tetrapyrrole biosynthesis genes and a collection of unknown genes, suggesting that the cluster may be responsible for tolyporphin production. Knowledge of the genome and the gene cluster sharply focuses research to identify related cyanobacterial producers of tolyporphins and delineate the tolyporphin biosynthetic pathway.
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Brückner C. Tolyporphin—An Unusual Green Chlorin‐like Dioxobacteriochlorin. Photochem Photobiol 2017; 93:1320-1325. [DOI: 10.1111/php.12787] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Accepted: 04/11/2017] [Indexed: 12/25/2022]
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