Regensburg 2013 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 2: Proteins

BP 2.9: Vortrag

Montag, 11. März 2013, 12:00–12:15, H44

Regulatory mechanism of the light-activable DNA-binding switch LOV-TAP : A computer simulation study — Emanuel Peter, Bernhard Dick, and •Stephan A Baeurle — Institute of Physical and Theoretical Chemistry, University of Regensburg, D-93040 Regensburg, Germany

The spatio-temporal control of gene expression is fundamental to elucidate cell proliferation and deregulation phenomena in living systems. Novel approaches based on light-sensitive multi-protein complexes have recently been devised, showing promising perspectives for the reversible modulation of the DNA-transcriptional activity in vivo. This has lately been demonstrated in a striking way through the generation of the artificial protein construct light-oxygen-voltage (LOV)-tryptophan-activated protein (TAP), in which the LOV2-Jalpha photoswitch of phototropin1 from Avena sativa (AsLOV2-Jalpha) has been ligated to the tryptophan-repressor (TrpR) protein from Escherichia coli. Here, we elucidate the early stages of the light-induced regulatory mechanism of LOV-TAP at the molecular level, using the noninvasive molecular dynamics simulation technique [1]. More specifically, we find that Cys450-FMN-adduct formation in the AsLOV2-Jalpha-binding pocket after photoexcitation induces the flexibilization through unfolding of a hairpin-like helix-loop-helix region interlinking the AsLOV2-Jalpha- and TrpR-domains, ultimately enabling the condensation of LOV-TAP onto the DNA surface.

[1] E. Peter, B. Dick, S.A. Baeurle, Prot. Struct. Funct. Bioinf., in press (2012); doi:10.1002/prot.24196