Nonradiative energy transfer in oligopeptide chains generated by a monte-cralo mehod including long-range interactions
✍ Scribed by Marc Leclerc; Samuel Prémilat; Anne Englert
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 1978
- Tongue
- English
- Weight
- 763 KB
- Volume
- 17
- Category
- Article
- ISSN
- 0006-3525
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✦ Synopsis
A Monte-Carlo method including long-range interactions is used to generate oligopeptide chains in random-coil state. The chains are composed of 4,9, or 14 repeating units and are labeled with the luminophores tyrosine or tryptophan. Interactions with a solvent (water) are taken into account in the calculations through modifications of the semiempirical potential-energy functions. The chains represent oligopeptides composed of hydrophobic or hydrophilic amino acid residues. Various properties relevant to the interpretation of nonradiative energy-transfer experiments, such as the average value of the orientation factor for dipole-dipole interaction of the luminophores, ( K ~) , the distribution function of the distances between the luminophores f(rl), the efficiencies of energy transfer in the static and dynamic averaging regimes, ( T ) , and ( T ) d , as well as the fluorescence decay I ( t ) of the donor luminophore in various averaging conditions, are computed. It is shown that, for all chains considered, ( K ~) is not very far from 0.67 and that ( T),s and ( T ) d have completely different values.
Due to the small extent of correlation between the distances rl and the mutual orientations of.the luminophores, the decay kinetics ( I ( t ) ), corresponding to a static averaging regime can be expressed in terms of distribution functions f(rl). These results are in agreement with those obtained previously for the unperturbed chain model.