Fluorescence characteristics of phytochrome and biliverdins

Song, Pill‐Soon; Chae, Quae; Lightner, David A.; Briggs, Winslow R.; Hopkins, D. W.

doi:10.1021/ja00804a069

Cited by 37 publications

(13 citation statements)

References 3 publications

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“…Our results clarify and enlarge previous findings [3-51 which in part have been contradictory [4] [5]. Furthermore, our investigation has been carried out with a sample of 2 of unequivocally established homogeneity, an aspect which apparently may not have been assessed with sufficient scrutiny in previous spectroscopic ~t u d i e s~-~) .…”

supporting

confidence: 85%

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The fluorescence of biliverdin dimethyl ester

Braslavsky

Holzwarth

Lehner

et al. 1978

Helvetica Chimica Acta

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SummaryFreshly prepared solutions of biliverdin dimethyl ester (2) in ethanol showed fluorescence maxima at 710 and 770 nm [DF= 1.1 .(room temperature) and 5.0.(77 K)]. The maxima of monoprotonated 2 at 77 K were shifted to 725 and 806 nm and the quantum yield was increased to 2.6 .This acid effect was reversible by neutralization with base. When a neutral solution was kept standing in the dark at room temperature, or when an acidic solution was neutralized by base, an additional fluorescence maximum at 500 nm with a mirror image excitation spectrum with 2,,,=470 nm developed, which disappeared on addition of acid and which is attributed to a chemical change of 2.Biliverdin (1)') is an intermediate in the heme catabolism of the bile pigment bilirubin') [l], and it appears to be related to the chromophore of phytochrome, a morphogenically active plant chromoprotein [2].

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supporting

confidence: 85%

“…The considerable sensitivity towards acid and the change of the fluorescence of dissolved 2 as a function of time finally may clarify some hitherto contradictory reports on the emission of biliverdin esters [4] [ 5 ] . The absorption and emission described for 2 by Song et a/.…”

mentioning

confidence: 96%

The fluorescence of biliverdin dimethyl ester

Braslavsky

Holzwarth

Lehner

et al. 1978

Helvetica Chimica Acta

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“…While the other species-with = 395 and 420 nm, respectivelyis detected in ethanol only at 77 K as a very small fraction (Fig. 2), appreciable contributions of both species to the fluorescence are observed in ethyl lactate at room temperature ( Fig.…”

Section: Spectroscopy Of Bilirubin Dimethyl Ester In Solution Coexismentioning

confidence: 92%

“…For example, in ethanol at 77 for the minor "395 nm" component of the dual emission were obtained. The relative lifetimes are reversed at room temperature.…”

Section: Spectroscopy Of Bilirubin Dimethyl Ester In Solution Coexismentioning

confidence: 99%

Solution Conformations, Photophysics, and Photochemistry of Bile Pigments; Bilirubin and Biliverdin, Dimethyl Esters and Related Linear Tetrapyrroles

Braslavsky

Holzwarth

Schaffner

1983

Angew. Chem. Int. Ed. Engl.

106

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Dedicated to Professor Giinther 0. Schenck on the occasion of his 70th birthdayBilirubin and biliverdin dimethyl esters (BRE and BVE, respectively) and related linear tetrapyrroles have been studied using a combination of photochemical and spectroscopic techniques, the latter including absorption, fluorescence, fluorescence excitation, mediuminduced circular dichroism, and proton magnetic resonance. Both types of tetrapyrroles form mixtures of different topological isomers in very dilute solutions. In the case of the bilirubins the heterogeneity of the solutions is caused by two coexisting conformers with different orientations of the A/B and C/D pyrromethenone moieties with respect to each other. The spectral properties of one conformer resemble the isolated parent pyrromethenone, whereas those of the other result from electronic coupling of the two subchromophores presumably held in a "ridge tile"-like orientation. C-C rotations at the C-5 and C-15 bridges substantially compete in both components with the photochemical channels (E+Z isomerization and lumirubin formation) for the radiationless deactivation of the excited singlet state. The more rigid "ridge tile" component additionally undergoes hydrogen bond-mediated deactivation, and it photoisomerizes more efficiently. The situation is markedly more complex with the biliverdins. In order to obtain a more detailed insight into the mechanisms of the radiationless excited-state processes, time-resolved optoacoustic spectroscopy and ultrafast absorption (pump-probe) and fluorescence detection (singlephoton-timing) techniques were used to supplement the stationary methods. The solution mixtures are composed of a (family of) helically coiled all-2,all-syn species, and of species differing from the former by stretched arrangements of the rings B and C around the central C-10 bridge (E-anti, E-syn, and Z-anti). Two excited singlet states with picosecond lifetimes are attributed to either one or two coiled ground-state forms, and two remarkably long-lived nanosecond excited states arise each from a stretched ground state. The radiationless deactivation of the shorter-lived of the picosecond states is brought about by ultrafast intramolecular proton transfer between the B/C nitrogen atoms, in addition to the C-C rotational modes operative in both. Z-+E photoisomerization is also an appreciable deactivation channel of excited biliverdin dimethyl ester. It is confined to the central C-10 double bond and selectively affords a stretched isomer (10E-anti), which thermally reforms the coiled starting material at room temperature via a sequence of tautomerization and C-C rotation. Heating or ultrasonic treatment can reverse this sequence and drive it farther to populate another stretched isomer (10E-syn) which is thermally stable at room temperature. This stretched form aggregates (presumably to dimers) already at concentrations at which the coiled species still appears to be fully monomeric.

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“…Fluorescence from BVDME in ethanol at 77 K has been observed near 725 and 450mn after excitation at 380nm (Song et al, 1973). The two-band fluorescence emission of BVDME has been suggested to arise from an impurity (Gautron et at., 1976).…”

Section: H Hnmentioning

confidence: 99%