Selective Photorelease of Active Chemicals Locked by the Flavoprotein Dodecin

Gilbert Nöll 1Martin Grininger Dieter Oesterhelt Sibylle Trawöger Eva-Kathrin Sinner Madlene Von Sanden-Flohe Bernhard Dick Tanja Nöll 

1. Lund University, Department of Analytical Chemistry, Lund SE-221 00, Sweden

Abstract

Dodecin from Halobacterium salinarum is a dodecameric, hollow-spherical flavoprotein which contains six flavin binding sites. In each binding site, two flavins are arranged in an aromatic tetrade between two tryptophan residues. Dodecin binds not only native but also artificial flavins with high binding affinities. The dissociation constants for flavin binding to dodecin were determined by titration of the fluorescent ligand with the apoprotein at room temperature. When incorporated into apododecin, the flavin fluorescence is quenched, probably by electron transfer from tryptophan to the excited flavin state. Reduction of the flavin ligand induces the dissociation of the holocomplex into apododecin and free flavin. Inspired by the binding mode and the redox characteristics of dodecin, we are developing an electrochemically active flavin modified electrode surface (electrode - molecular wire - flavin) which is able to bind or release dodecin apoprotein triggered by the redox potential. Possible applications range from the control or transport of single molecular assemblies containing dodecin apoprotein, up to the development of bioelectrochemical data storage devices with an electrochemical input (write) and an optical (fluorescence sensitive) output (read). Additionally we have synthesized flavin ligands which can be tethered to various molecules of interest by an amide or an ester bond. Irradiation of dodecin with blue-light in the presence of EDTA results in photochemical reduction of these flavins followed by their release. We are working on a protein based molecular transport system triggered by light. This system will allow the binding and release of functional molecules tethered to flavins.

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Presentation: Short communication at SMCBS'2007 International Workshop, by Gilbert Nöll
See On-line Journal of SMCBS'2007 International Workshop

Submitted: 2007-08-31 21:30
Revised:   2009-06-07 00:44
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