Photophysics of ANS. I. Protein-ANS complexes: Intestinal fatty acid binding protein and single-trp mutants

Elena Klimtchuk, Sergei Venyaminov, Elizabeth Kurian, William Wessels, William Kirk, Franklyn G. Prendergast

Research output: Contribution to journalArticle

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Abstract

We continue investigations into the physical chemistry of intestinal fatty acid binding protein, I-FABP, and its interaction with ANS and other ligands [cf references [Kirk, W., E. Kurian, and F. Prendergast. 1996. Characterization of the sources of protein-ligand affinity: 1-sulfonato-8-anilinonaphthalene binding to intestinal fatty acid binding protein. Biophys. J. 70: 69-83., Kurian, E., W. Kirk, and F. Prendergast. 1996. Affinity of fatty acid for rRat intestinal fatty acid binding protein: Further examination. Biochemistry. 35:3865-74]. The photophysics of the wt protein is compared with that in two mutants which lack respectively one or the other of two trp moieties, one of which, trp 82, is located near the binding region for the polar head group of ligands. These studies afford a look into how the fluorescence of the wt protein is established, that is, as an almost direct sum of the fluorescence of the two individual trp residues, and how this fluorescence is quenched upon binding to ANS. Though we have access to all the relevant spectroscopic and geometric information necessary to specify in detail the Foerster-Dexter energy transfer model, the quenching process is not explicable in terms of very-weak coupling, as is usually assumed in fluorescence studies in protein systems, but in terms of a stronger effect which goes beyond the simple very-weak dipole:dipole formalism. The quenching of trp emission by bound ANS is not as great as that anticipated by ordinary resonance energy transfer, neither is the quenching observed in the reduced lifetimes of the trp emission upon ANS binding as great as that observed in steady-state intensity. However the observed steady-state quenching is explicable in terms derived from the lifetime measurements, together with observed spectral band shifts, by the exciton coupling model we invoke here.

Original languageEnglish (US)
Pages (from-to)1-12
Number of pages12
JournalBiophysical Chemistry
Volume125
Issue number1
DOIs
StatePublished - Jan 2007

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Astronomical Netherlands Satellite
Fatty Acid-Binding Proteins
fatty acids
Quenching
Fluorescence
proteins
Energy Transfer
Ligands
Energy transfer
quenching
Proteins
Physical Chemistry
fluorescence
Cold Climate
Physical chemistry
Biochemistry
ligands
affinity
energy transfer
Fatty Acids

Keywords

  • 1,8 ANS
  • Exciton coupling
  • Non-Foerster energy transfer

ASJC Scopus subject areas

  • Biochemistry
  • Physical and Theoretical Chemistry
  • Biophysics

Cite this

Klimtchuk, E., Venyaminov, S., Kurian, E., Wessels, W., Kirk, W., & Prendergast, F. G. (2007). Photophysics of ANS. I. Protein-ANS complexes: Intestinal fatty acid binding protein and single-trp mutants. Biophysical Chemistry, 125(1), 1-12. https://doi.org/10.1016/j.bpc.2006.07.016

Photophysics of ANS. I. Protein-ANS complexes : Intestinal fatty acid binding protein and single-trp mutants. / Klimtchuk, Elena; Venyaminov, Sergei; Kurian, Elizabeth; Wessels, William; Kirk, William; Prendergast, Franklyn G.

In: Biophysical Chemistry, Vol. 125, No. 1, 01.2007, p. 1-12.

Research output: Contribution to journalArticle

Klimtchuk, E, Venyaminov, S, Kurian, E, Wessels, W, Kirk, W & Prendergast, FG 2007, 'Photophysics of ANS. I. Protein-ANS complexes: Intestinal fatty acid binding protein and single-trp mutants', Biophysical Chemistry, vol. 125, no. 1, pp. 1-12. https://doi.org/10.1016/j.bpc.2006.07.016
Klimtchuk, Elena ; Venyaminov, Sergei ; Kurian, Elizabeth ; Wessels, William ; Kirk, William ; Prendergast, Franklyn G. / Photophysics of ANS. I. Protein-ANS complexes : Intestinal fatty acid binding protein and single-trp mutants. In: Biophysical Chemistry. 2007 ; Vol. 125, No. 1. pp. 1-12.
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