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SYBP: Biophotonik

SYBP 3: Einzelmolekülmethoden III

SYBP 3.1: Hauptvortrag

Donnerstag, 7. März 2002, 16:30–17:00, HS 11/215

Optical spectroscopy of single proteins — •Andreas Zumbusch — LMU München, Dept. Chemie, Butenandtstr.11, 81377 München

Recently, different techniques for the optical detection of single molecules at room temperature have become available. One important focus of such studies are investigations of single fluorescent proteins. The virtues of the different single molecule techniques will be exemplified by studies of the green fluorescent protein (GFP) and of phycoerythrocyanin (PEC). While single molecule imaging is successfully employed for elucidating the emission behavior of single PEC molecules, the population of non-emitting dark states in the GFP are more conveniently studied with fluorescence correlation spectroscopy (FCS). Using FCS with a newly developed two-color excitation scheme, allows us to collect information about the identity of the dark states absorption spectra. It will be shown how the increase in fluorescence signal obtained by double resonance excitation can be exploited for obtaining brighter images in live cell and single molecule microscopy with the GFP. Promising first results of an extension of the two color excitation scheme to non-electronic contrast generation will be presented.