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FLUORESCENCE QUANTUM YIELDS OF 124-kDa PHYTOCHROME FROM OAT UPON EXCITATION WITHIN DIFFERENT ABSORPTION BANDS 总被引:1,自引:0,他引:1
Claudio G. Colombano Silvia E. Braslavsky Alfred R. Holzwarth Kurt Schaffner 《Photochemistry and photobiology》1990,52(1):19-22
Abstract— A fluorescence quantum yield (emission at650–850 nm) of π= (2.3 ± 0.3)10−3 was measured for the red-absorbing form (Pr) of 124-kDa phytochrome from etiolated oat seedlings ( Avena sativa ) upon excitation in the Soret band at Λexc = 380 nm. The small difference between this value and the previously determined quantum yield with Λexc = 640 nm, π= (3.5 ± 0.4)10−3 is attributed to a blue-absorbing emitter responsible for the "anomalous" or "blue" emission of the chromoprotein in the region from ca. 400 to 550 nm. The absorption of Pr at 380 nm is consequently somewhat lower than that measured directly from the spectrum. Processes from upper excited states of the Pr phytochromobilin-derived chromophore other than rapid relaxation to the emitting state are not important. A quantum yield of Φ ' 1.2 times 10−3 is estimated for the blue fluorescence. The proportion of the blue emitters relative to Pr appears to be relatively high. 相似文献
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Mossetti R Caprioglio D Colombano G Tron GC Pirali T 《Organic & biomolecular chemistry》2011,9(5):1627-1631
α-Isocyanoacetamides, acyl chlorides and dialkylacetylenedicarboxylates undergo a smooth multicomponent reaction to produce dialkyl 2-acyl-5-aminofuran-3,4-dicarboxylates in good yield. The scope and mechanism of this new multicomponent transformation are discussed. 相似文献
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Dr. Alessandro Colombano Dr. Luca Dalponte Dr. Sergio Dall'Angelo Claudia Clemente Dr. Mohannad Idress Ahmad Ghazal Dr. Wael E. Houssen 《Angewandte Chemie (International ed. in English)》2023,62(16):e202215979
Aromatic prenyltransferases from cyanobactin biosynthetic pathways catalyse the chemoselective and regioselective intramolecular transfer of prenyl/geranyl groups from isoprene donors to an electron-rich position in these macrocyclic and linear peptides. These enzymes often demonstrate relaxed substrate specificity and are considered useful biocatalysts for structural diversification of peptides. Herein, we assess the isoprene donor specificity of the N1-tryptophan prenyltransferase AcyF from the anacyclamide A8P pathway using a library of 22 synthetic alkyl pyrophosphate analogues, of which many display reactive groups that are amenable to additional functionalization. We further used AcyF to introduce a reactive moiety into a tryptophan-containing cyclic peptide and subsequently used click chemistry to fluorescently label the enzymatically modified peptide. This chemoenzymatic strategy allows late-stage modification of peptides and is useful for many applications. 相似文献
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