Nanoscience Center

Nanoscience seminars

Seminars are arranged during the terms on weekly bases on Friday afternoons at 1 o'clock with coffee, talk starts 13:15 in YN121 in NSC. Welcome!

Wednesday 12.8. in YAA305 at 1 o'clock with coffee, talk starts 13:15

Brigitte Buchli
University of Zürich


Kinetic and dynamic responses of proteins utilizing time-resolved IR spectroscopy and single-molecule fluorescence spectroscopy


By covalently linking an azobenzene photoswitch across the binding groove of an allosteric protein domain, a conformational transition can be initiated by a laser pulse [1]. This transition mimics the conformational change of the unmodified domain upon ligand binding. We have studied this light induced transition by time-resolved IR spectroscopy. So far, we have probed two IR absorption bands: First, the amide I band which arises from the carbonyl stretch vibration of all amide groups in the protein and is sensitive to overall structural changes, and second, a vibration localized on the photoswitch, which is sensitive to the local environment of the photoswitch, namely the opening of the binding groove. We have found that the binding groove opens on a timescale of 100 ns in a non-exponential manner, once the binding groove has equilibrated, the protein conformation still continues to change elsewhere. Currently, we are incorporating site-specific IR labels, to learn more about the response of the protein to the perturbation of the binding groove.
In a second project we have studied the dynamics in an unfolded state of a protein. We have labeled the protein with two fluorescent dyes at different positions in the protein and used single-molecule Förster resonance energy transfer (FRET) and fluorescence correlation spectroscopy (FCS) to reveal the dynamics in the unfolded state [2]. This allowed us to quantify the extent of internal friction in unfolded protein chains.

1.    Buchli B., Waldauer S. A., Walser R., Donten M., Pfister R., Blöchliger N., Steiner S., Caflisch A., Zerbe O., Hamm P. (2013) Kinetic response of a photoperturbed allosteric protein. Proc. Natl. Acad. Sci. U.S.A. 110, 11725-11730.
2.    Soranno A., Buchli B., Nettels D., Cheng R. R., Müller-Späth S., Pfeil S. H., Hoffmann A., Lipman E. A., Makarov D. E., Schuler B. (2012) Quantifying internal friction in unfolded and intrinsically disordered proteins with single-molecule spectroscopy. Proc. Natl. Acad. Sci. U.S.A. 109, 17800-17806.

 

NANOSEMINARS AUTUMN 2015

DateTitle                                          

Speaker

Host
12.8 Kinetic and dynamic responses of proteins utilizing time-resolved IR spectroscopy and single-molecule fluorescence spectroscopy Brigitte Buchli
University of Zürich
Ihalainen
11.9 Nanomaster seminars Johannes Lehmuskoski
Kevin Roberts
Ville Valkiala
Johansson
18.9 Nanomaster seminars Niko-Ville Hakkola
Sisi Xie
Joonas Pylväinen
Johansson


The previous seminars in 2015 2014 2013 2012 2011 2010 2009 2008 2007

 

Seminars in:

Department of Physics Molecular Recognition

Contact Information

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Nanoscience Center
P.O.Box 35
FI-40014 University of Jyväskylä
FINLAND
Tel: +358 50 3956 020
Fax: +358 14 617 412

Street address and office:
YN213
Survontie 9 C
40500 Jyväskylä

E-mail: nanoscience@jyu.fi

 

Location