Berlin 2012 – scientific programme

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BP: Fachverband Biologische Physik

BP 7: Posters: Proteins

BP 7.38: Poster

Monday, March 26, 2012, 17:30–19:30, Poster A

SMS - FRET spectroscopy has emerged as a versatile tool in life sciences. — •Phillip Kroehn and Jörg Enderlein — Drittes Physikalisches Institut Göttingen

The applications range from protein-protein interactions and imaging microscopy to fast dynamic processes such as protein folding.

For SMS-FRET measurements in protein folding studies, site specific labelling of the protein with a donor and acceptor dye is limited to the reaction of cystein and lysine residues. Depending on the site of the protein two approaches overcome the uncertainty of random labelling.

1)*For small proteins or peptides up to 50 aa, solid phase peptide synthesis (SPPS) is the method of choice. By using aa with different protective groups site specific coupling to virtual all residues is possible.

2)*For larger proteins two new evolving methods enable the site specific coupling of dyes: a) the so called orthogonal-system allows the insertion of unnatural aa via bacterial expression in the polypeptide chain, the dye is then specifically coupled to the functional side chain of the unnatural aa. (Schulz et al J Am. Chem. Soc., 2008). b) Intein mediated protein ligation can be used to efficiently fuse short peptides with attached fluorophores to expressed proteins (Grant et al, Biol. Chem., 2006).