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Isomers in the excited state of electron-transferring flavoprotein from Megasphaera elsdenii: Spectral resolution from the time-resolved fluorescence spectra

Paper ID Volume ID Publish Year Pages File Format Full-Text
30598 44491 2008 7 PDF Available
Title
Isomers in the excited state of electron-transferring flavoprotein from Megasphaera elsdenii: Spectral resolution from the time-resolved fluorescence spectra
Abstract

Electron-transferring flavoprotein (Holo-ETF) from Megasphaera elsdenii contains two FAD’s, one of which easily dissociates to form Iso-ETF (contains one FAD). Time-resolved fluorescence of FAD in Iso-ETF, and Holo-ETF were measured at 5 °C and 25 °C. Wavelength-dependent fluorescence decays of the both ETF at 5 °C and 25 °C were analyzed to resolve them into two independent spectra. It was found that Iso-ETF displayed two spectra with lifetime of 0.605 ns (emission peak, 508 nm) and with lifetime of 1.70 ns (emission peak, 540 nm) at 5 °C, and with lifetime of 0.693 ns (emission peak, 508 nm) and with lifetime of 2.75 ns (emission peak, 540 nm) at 25 °C. Holo-ETF displayed two spectra with lifetime of 0.739 ns (emission peak, 508 nm) and with lifetime of 2.06 ns (emission peak, 545 nm) at 5 °C, and with lifetime of 0.711 ns (emission peak, 527 nm) and with lifetime of 3.08 ns (emission peak, 540 nm) at 25 °C. Thus fluorescence lifetimes of every spectrum increased upon elevating temperature. Emission peaks Iso-ETF did not change much upon elevating temperature. Activation enthalpy changes, activation entropy changes and activation Gibbs energy changes of quenching rates all displayed negative. Two emission species in the both ETF may be hydrogen-bonding isomers, because isoalloxazine ring of FAD contains four hydrogen acceptors and one donor.

Keywords
Electron-transferring flavoprotein from Megasphaera elsdenii; Time-resolved fluorescence; Lifetime; Spectral resolution; Flavin; Decay associate spectra
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Isomers in the excited state of electron-transferring flavoprotein from Megasphaera elsdenii: Spectral resolution from the time-resolved fluorescence spectra
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 90, Issue 2, 27 February 2008, Pages 134–140
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
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