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BP: Fachverband Biologische Physik

BP 1: Proteins I

BP 1.10: Vortrag

Montag, 26. März 2012, 12:30–12:45, H 1058

Single-molecule fluorescence spectroscopy of the structure and dynamics of the spliceosomal complex — •Mira Prior¹, Thomas Orth², Peter Odenwälder², Ingo Gregor¹, Reinhard Lührmann², and Jörg Enderlein¹ — ¹Third Institute of Physics, Göttingen — ²Max Planck Institute for Biophysical Chemistry, Göttingen

The spliceosome is the cellular machinery responsible for removing non-coding introns from precursor mRNA. During its catalytic action the spliceosome undergoes compositional and conformational changes. We are investigating the conditions for recruitment and release of particular proteins during the splicing steps. We determine how the changes occur (stepwise or in a correlated manner) and the roles of certain spliceosomal RNA helicases in the restructuring of the complex. The spectroscopic methods we use for investigating the spliceosomal complex are Dual-Focus Fluorescence Correlation Spectroscopy (2fFCS) and Dual-Color-Fluorescence Cross-Correlation Spectroscopy (2-color-FCCS). These methods allow for studying structural and dynamical properties of proteins and small nuclear ribonucleoproteins (snRNPs). 2-color-FCCS in combination with 2fFCS enables the observation of protein-protein interactions and the determination of dissociation constants for protein-protein and protein-mRNA bindings which could not be resolved with standard biochemical methods. In our experiments we focus on the B to Bact transition followed by LSm ring proteins, the thermally-stable splicing factor Cwc25 and on the proteins of the snRNP U2 complex.