umu.sePublications
Change search
ReferencesLink to record
Permanent link

Direct link
On the quantitative molecular analysis of electronic energy transfer within donor–acceptor pairs
Umeå University, Faculty of Science and Technology, Chemistry.
Umeå University, Faculty of Science and Technology, Chemistry.
Umeå University, Faculty of Science and Technology, Chemistry.
Umeå University, Faculty of Science and Technology, Chemistry.
2007 (English)In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, Vol. 9, 1941-51 p.Article in journal (Refereed) Published
Abstract [en]

An extended Förster theory (EFT) on electronic energy transfer is presented for the quantitative analysis of time-resolved fluorescence lifetime and depolarisation experiments. The EFT, which was derived from the stochastic Liouville equation, yields microscopic information concerning the reorientation correlation times, the order parameters, as well as inter chromophoric distances. Weakly interacting donor and acceptor groups, which reorient and interact in a pair wise fashion, are considered, under isotropic and anisotropic conditions. For the analysis of experiments it is shown that not only do we need to consider the orientational distributions of the transition dipoles, but the internal reorienting molecular dynamics within the pair which is of even greater importance. The latter determines the shape as well as the rate of the observed donor fluorescence and depolarisation decays, which are most often not mono-exponential functions. It is shown that the commonly used Förster theory is a special case of the EFT. Strategies are presented for applying the EFT, which makes use of Brownian dynamics simulation.

Place, publisher, year, edition, pages
2007. Vol. 9, 1941-51 p.
Identifiers
URN: urn:nbn:se:umu:diva-13009DOI: doi:10.1039/b614817dOAI: oai:DiVA.org:umu-13009DiVA: diva2:152680
Available from: 2007-06-26 Created: 2007-06-26 Last updated: 2009-10-28Bibliographically approved
In thesis
1. On the quantitative analysis of electronic energy transfer/migration in proteins studied by fluorescence spectroscopy
Open this publication in new window or tab >>On the quantitative analysis of electronic energy transfer/migration in proteins studied by fluorescence spectroscopy
2007 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Two recently developed theories of electronic energy transfer/migration were for the first time applied to real protein systems for extracting molecular distances. The partial donor-donor energy migration (PDDEM) is an extension to the previously developed donor-donor energy migration (DDEM, F Bergström et al PNAS 96, 1999, 12477) which allows using chemically identical but photophysically different fluorophores in energy migration experiments. A method based on fluorescence quenching was investigated and applied to create an asymmetric energy migration between fluorophores which were covalently and specifically attached to plasminogen activator inhibitor type 2 (PAI-2). It was also shown experimentally that distance information can be obtained if the fluorescence relaxation for photophysically identical donors, exhibits multi-exponential relaxation.

An extended Förster theory (EFT) that was previously derived (L. B.-Å. Johansson et al J. Chem. Phys., 1996, 105) ha been developed for analysis of donor-acceptor energy transfer systems as well as DDEM systems. Recently the EFT was also applied to determine intra molecular distances in the protein plasminogen activator inhibitor type 1 (PAI-1) which was labelled with a sulfhydryl specific derivative of BODIPY. The EFT explicitly accounts for the time-dependent reorientations which in a complex manner influence the rate of electronic energy transfer/migration. This difficulty is related to the “k2-problem”, which has been solved. It is also shown experimentally that the time-correlated single-photon counting (TCSPC) data is sensitive to the mutual configuration between the interacting fluorophores. To increase the accuracy in the extracted parameters it is furthermore suggested to collect the fluorescence data under various physico-chemical conditions. It was also shown that the Förster theory is only valid in the initial part of the fluorescence decay.

Place, publisher, year, edition, pages
Umeå: Kemi, 2007. 46 p.
Keyword
Biophysical Chemistry
National Category
Physical Chemistry
Identifiers
urn:nbn:se:umu:diva-1009 (URN)978-91-7264-263-8 (ISBN)
Public defence
2007-03-02, KBC3A9, KBC-huset, 901 87, Umeå, 10:30 (English)
Opponent
Supervisors
Available from: 2007-02-15 Created: 2007-02-15 Last updated: 2009-10-28Bibliographically approved
2. Extended Förster Theory of Electronic Energy Transport within Pairs of Reorienting Chromophoric Molecules
Open this publication in new window or tab >>Extended Förster Theory of Electronic Energy Transport within Pairs of Reorienting Chromophoric Molecules
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

An extended Förster theory (EFT), previously derived (L. B.-Å. Johansson et al. J. Chem. Phys., 1996,105) has theoretically been adapted and used in simulations of donor-acceptor energy transfer (DAET), which is a process often referred to as FRET. It was shown that the classical Förster theory is only valid in the initial part of the fluorescence decay. In this thesis an EFT is derived and outlined for electronic energy transport between two fluorescent molecules which are chemically identical, but photophysically non-identical. The energy migration within such asymmetric pairs is partially reversible and therefore referred to as partial donor-donor energy migration (PDDEM). The previously derived model of PDDEM (S. V. Kalinin et al. Spectrochim Acta Part A, 2002,58) is an approximation of the EFT. In particular, the EFT accounts for the time-dependent reorientations as well as the distance that influence the rate of electronic energy migration. The reorientation of the fluorophores transition dipole moments has been simulated using Brownian dynamics. As a result, the related “k2-problem” has been solved. The EFT of PDDEM has also been studied regarding the effect of PDDEM on experimental observables e.g. quantum yield of fluorescence and steady-state anisotropies

Place, publisher, year, edition, pages
Umeå: VMC-KBC, 2009. 37 p.
Keyword
electronic energy migration/transfer, extended Förster theory, orientation factor, DDEM, PDDEM, time-resolved fluorescence anisotropy, time-correlated single photon counting, Brownian dynamics
Research subject
Physical Chemistry
Identifiers
urn:nbn:se:umu:diva-22471 (URN)978-91-7264-783-1 (ISBN)
Public defence
2009-06-05, KB3A9, KBC huset, Umeå Universitet, 13:15 (English)
Opponent
Supervisors
Available from: 2009-05-15 Created: 2009-05-11 Last updated: 2009-05-15Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Norlin, NilsWestlund, Per-OlofJohansson, Lennart B-Å
By organisation
Chemistry
In the same journal
Physical Chemistry, Chemical Physics - PCCP

Search outside of DiVA

GoogleGoogle Scholar

Altmetric score

Total: 86 hits
ReferencesLink to record
Permanent link

Direct link