Lennart B.-Å. Johansson: Polarised light spectroscopy and energy migration/transfer with applications in biosciences

The project aims at a molecular-level-development of polarised light spectroscopy for insights into complex biostructures, in particular the dynamics, structure and functioning of proteins related to e.g. the folding and formation of regular protein aggregates (= non-covalent polymers).

A new approach to the theoretical description and experimental studies of bio-macromolecular structures is used, which is based on electronic energy transport between chemically identical or different fluorescent groups. These extrinsic or intrinsic groups are localised at specific positions, e.g. in a protein structure. Time-resolved polarised fluorescence spectroscopic experiments are applied in studies of these groups in the absence and presence of energy transport. The energy migration/transfer among fluorophores is described within a recently developed extended Förster theory (EFT), which brings the theoretical analysis of experimental data to the same level of molecular detail as in ESR and NMR spectroscopy. The EFT involves stochastic equations, which necessitate the use of Brownian dynamics simulations.
In another branch of the project, fundamental aspects of enhanced one-photon and two-photon excited fluorescence are studied. Potential applications of these processes are, for instance as amplifiers of chemical sensors.

OPEN: PhD student position
Fluorescence spectroscopy & extended Förster theory development with applications to structure-function studies of proteins
In the PhD project, time-resolved fluorescence depolarisation experiments are performed and analysed by means of ongoing and recent theoretical advancements of electronic energy transfer. Applications of computational methods (e.g. Brownian dynamics simulations) are crucial. The project aims at:
- applying currently developed methods for the determination of structure and structural changes of globular proteins (e.g. protein folding), as well as regular protein aggregates (e.g. amyloid and fibril structures)
- a continuing development of extended Förster theory and its testing on synthetic and experimental data obtained by one- as well as two-photon excited fluorescence. Time-resolved fluorescence data are recorded by using the single-photon counting technique.
The project involves interdisciplinary collaborations with theoretical chemists, biochemists, medical chemists as well as plant physiologists at Umeå University.
For more information, please contact Prof. Lennart B.-Å. Johansson: Phone +46-(0)90-786 51 49; Cell phone +46 702122521; E-mail: lennart.johansson@chem.umu.se

Publications

Author

Title

Year sorteringsordning

Fulltext

Mikaelsson, Therese
Ådén, Jörgen
Wittung-Stafshede, Pernilla; et al.

Macromolecular crowding effects on two homologs of ribosomal protein S16: protein-dependent structural changes and local interactions
Biophysical Journal, 107(2): 401-410

2014

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Mikaelsson, Therese
Ådén, Jörgen
Johansson, Lennart B-Å; et al.

Direct Observation of Protein Unfolded State Compaction in the Presence of Macromolecular Crowding
Biophysical Journal, 104(3): 694-704

2013

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Krishnan, K Syam
Bengtsson, Christoffer
Good, James A D; et al.

Synthesis of fluorescent ring-fused 2-pyridone peptidomimetics
Journal of Organic Chemistry, 78(23): 12207-12213

2013

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Humpolickova, Jana
Stefl, Martin
Sachl, Radek; et al.

Dynamics and size of crosslinking-induced lipid nanodomains in model membranes
Biophysical Journal, 102(3): 294a-

2012

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Stefl, Martin
Sachl, Radek
Humpolickova, Jana; et al.

Dynamics and size of cross-linking-induced lipid Nanodomains in model Membranes
Biophysical Journal, 102(9): 2104-2113

2012

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Opanasyuk, Oleg
Mikaelsson, Therese
Ryderfors, Linus; et al.

On the analyses of fluorescence depolarisation data in the presence of electronic energy migration.: II. Applying & Evaluating Two-Photon Excited Fluorescence
Physical Chemistry, Chemical Physics - PCCP, 14: 1917-1922

2012

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Chorell, Erik
Pinkner, Jerome S
Bengtsson, Christoffer; et al.

Design and Synthesis of Fluorescent Pilicides and Curlicides: Bioactive Tools to Study Bacterial Virulence Mechanisms
Chemistry - A European Journal, 18(15): 4522-4532

2012

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Opanasyuk, Oleg
Johansson, Lennart B-Å

On the analyses of fluorescence depolarisation data in the presence of electronic energy migration: Part I. Theory and general description
Physical Chemistry, Chemical Physics - PCCP, 14: 1907-1916

2012

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Sachl, Radek
Johansson, Lennart B-Å
Hof, Martin

Förster Resonance Energy Transfer (FRET) between Heterogeneously Distributed Probes: Application to Lipid Nanodomains and Pores
International Journal of Molecular Sciences, 13(12): 16141-16156

2012

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Sachl, Radek
Humpolickova, Jana
Stefl, Martin; et al.

Limitations of electronic energy transfer in the determination of lipid nanodomain sizes
Biophysical Journal, 101(11): L60-L62

2011

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