- Biliverdin amides reveal roles for propionate side chains in bilin reductase recognition and in holophytochrome assembly and photoconversion
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Linear tetrapyrroles (bilins) perform important antioxidant and light-harvesting functions in cells from bacteria to humans. To explore the role of the propionate moieties in bilin metabolism, we report the semisynthesis of mono- and diamides of biliverdin IXα and those of its non-natural XIIIα isomer. Initially, these were examined as substrates of two types of NADPH-dependent biliverdin reductase, BVR and BvdR, and of the representative ferredoxin-dependent bilin reductase, phycocyanobilin:ferredoxin oxidoreductase (PcyA). Our studies indicate that the NADPH-dependent biliverdin reductases are less accommodating to amidation of the propionic acid side chains of biliverdin IXα than PcyA, which does not require free carboxylic acid side chains to yield its phytobilin product, phycocyanobilin. Bilin amides were also assembled with BV-type and phytobilin-type apophytochromes, demonstrating a role for the 8-propionate in the formation of the spectroscopically native Pr dark states of these biliprotein photosensors. Neither ionizable propionate side chain proved to be essential to primary photoisomerization for both classes of phytochromes, but an unsubstituted 12-propionate was required for full photointerconversion of phytobilin-type phytochrome Cph1. Taken together, these studies provide insight into the roles of the ionizable propionate side chains in substrate discrimination by two bilin reductase families while further underscoring the mechanistic differences between the photoconversions of BV-type and phytobilin-type phytochromes.
- Shang, Lixia,Rockwell, Nathan C.,Martin, Shelley S.,Lagarias, J. Clark
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experimental part
p. 6070 - 6082
(2011/04/23)
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- The detection of Hg2+ by cyanobacteria in aqueous media
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A tetrapyrrole-based chromophore was obtained through the methanolysis of C-phycocyanin extracted from Spirulina platensis, and was found to act as a selective receptor for Hg2+ at physiological pH conditions. The Royal Society of Chemistry 200
- Suresh, Moorthy,Mishra, Sanjiv K.,Mishra, Sandhya,Das, Amitava
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experimental part
p. 2496 - 2498
(2009/09/30)
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- An efficient method for the conversion of 2-bromo-5-tosylpyrroles to the corresponding 5-tosylpyrrolinones as the D-ring of phycocyanobilin derivatives
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2-Bromo-5-tosylpyrroles were efficiently converted to the corresponding 5-tosylpyrrolinones as the D-ring of phycocyanobilin (PCB) derivatives by treating with DMSO and Zn in TFA in the presence of a catalytic amount of iodine. PCB derivatives modified at the D-ring were prepared in free acid forms employing the resulting 5-tosylpyrrolinones toward structure/function analysis of phytochrome.
- Takeda, Shuzo,Jayasundera, Krishanthi Padmarani,Kakiuchi, Takashi,Kinoshita, Hideki,Inomata, Katsuhiko
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p. 590 - 591
(2007/10/03)
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- Total syntheses of phycocyanobilin derivatives bearing a modified A-ring toward the structure/function analysis of phytochrome
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Phycocyanobilin (PCB) derivatives bearing a modified A-ring, including 3,3′-dihydrogenated PCB derivatives, were efficiently synthesized in free acid forms by applying our original methods for the preparation of A-, A/B-, and C/D-ring components toward th
- Sawamoto, Daisuke,Nakamura, Hiroshi,Kinoshita, Hideki,Fujinami, Shuhei,Inomata, Katsuhiko
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p. 1398 - 1399
(2007/10/03)
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- Efficient synthesis of B- and C-rings components of phycobilin derivatives for structure/function analysis of phytochrome
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B- and C-Rings components of phycobilin derivatives were efficiently prepared starting from the corresponding lactones. This synthetic method made it possible to prepare not only phycocyanobilin (PCB), but also PCB derivatives having butanoic acid side chain(s) instead of propanoic one(s), regioselectively monoesterified PCB derivatives at C8 or C12, and regioisomers of PCB with respect to methyl and propanoic acid substituents of B- and C-rings for the first time toward the structure/function analysis of phytochrome.
- Ohta, Atsuko,Sawamoto, Daisuke,Jayasundera, Krishanthi Padmarani,Kinoshita, Hideki,Inomata, Katsuhiko
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p. 492 - 493
(2007/10/03)
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- An efficient method to construct the A,B-rings component toward total syntheses of phycocyanobilin and its derivative as a photoprobe
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Total syntheses of physocyanobilin and its derivative bearing a photoreactive group at the D-ring accomplished by developing a new and efficient method for the construction of A,B-rings component, which consists of the Wittig-type new coupling reaction of 4-(1-methoxyethyl or 1- tosylethyl)-3-methyl-5-tosyl-1,5-dihydro-2H-pyrrol-2-one and a 2-formyl pyrrole derivative in the presence of (n)Bu3P and a base, followed by reduction with aluminum amalgam and a subsequent acid or base treatment.
- Jayasundera, Krishanthi Padmarani,Kinoshita, Hideki,Inomata, Katsuhiko
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p. 497 - 500
(2007/10/03)
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- Total syntheses of (±)-phycocyanobilin and its derivatives bearing a photoreactive group at D-ring
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(±)-Phycocyanobilin and its derivatives bearing a photoreactive group at D-ring were first synthesized by the development of a new and convenient method for the preparation of A-ring, transesterification for propanoic acid side-chains of the pyrrole derivative common to B- and C-rings, and deprotection of allyl ester side-chains with a palladium catalyst to avoid migration of exocyclic olefin of A-ring.
- Kakiuchi, Takashi,Kato, Hirohide,Jayasundera, Krishanthi Padmarani,Higashi, Taijiro,Watabe, Kazuhiko,Sawamoto, Daisuke,Kinoshita, Hideki,Inomata, Katsuhiko
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p. 1001 - 1002
(2007/10/03)
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- Efficient construction of A,B-rings component for syntheses of phycocyanobilin and its derivative
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Total syntheses of phycocyanobilin and its photoactivatable derivative were accomplished by developing a new and versatile method for the construction of A,B-rings component, which consists of the Wittig-type new coupling reaction of 4-(1-methoxyethyl) -3
- Jayasundera, Krishanthi Padmarani,Kinoshita, Hideki,Inomata, Katsuhiko
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p. 1227 - 1228
(2007/10/03)
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