Distance distributions of short polypeptides recovered by fluorescence resonance energy transfer in the 10 A domain.
Fluorescence resonance energy transfer (FRET) between tryptophan (Trp) as donor and 2,3-diazabicyclo[2.2.2]oct-2-ene (Dbo) as acceptor was studied by steady-state and time-resolved fluorescence spectroscopy. The unique feature of this FRET pair is its exceptionally short Förster radius (10 A), which allows one to recover distance distributions in very short structureless peptides. The technique was applied to Trp-(GlySer)n-Dbo-NH2 peptides with n = 0-10, for which the average probe/quencher distance ranged between 8.7 and 13.7 A experimentally (in propylene glycol, analysis according to wormlike chain model) and 8.6-10.2 A theoretically (for n = 0-6, GROMOS96 molecular dynamics simulations). The larger FRET efficiency in steady-state compared to time-resolved fluorescence experiments was attributed to a static quenching component, suggesting that a small but significant part (ca. 10%) of the conformations are already in van der Waals contact when excitation occurs.
Sahoo
Harekrushna
H
School of Engineering and Science, International University Bremen, Campus Ring 1, D-28759 Bremen, Germany.
Roccatano
Danilo
D
Zacharias
Martin
M
Nau
Werner M
WM
D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry*; D003198:Computer Simulation; D031541:Fluorescence Resonance Energy Transfer; D015394:Molecular Structure; D010455:Peptides / Q000737:chemistry*; D013057:Spectrum Analysis; D014364:Tryptophan / Q000737:chemistry*
C484077:2,3-diazabicyclo(2.2.2)oct-2-ene; D019086:Bridged Bicyclo Compounds, Heterocyclic; D010455:Peptides; D014364:Tryptophan