FRET in a Synthetic Flavin- and Bilin-binding Protein

The last decade has seen development and application of a large number of novel fluorescence-based techniques that have revolutionized fluorescence microscopy in life sciences. Preferred tags for such applications are genetically encoded fluorescent proteins (FP), mostly derivatives of the green fluorescent protein (GFP). Combinations of FPs with wavelength-separated absorption/fluorescence properties serve as excellent tools for molecular interaction studies, for example, protein-protein complexes or enzyme-substrate interactions, based on the FRET phenomenon (Förster resonance energy transfer). However, alternatives are requested for experimental conditions where FP proteins or FP couples are not or less efficiently applicable. We here report as a "proof of principle" a specially designed, non-naturally occurring protein (LG1) carrying a combination of a flavin-binding LOV- and a photochromic bilin-binding GAF domain and demonstrate a FRET process between both chromophores

Bis[6-(3,5-dimethyl-1H-pyrazol-1-yl)picolinato]manganese(II) trihydrate

In the title complex, [Mn(C11H10N3O2)2]·3H2O, the MnII atom is coordinated by four N atoms and two O atoms in a distorted octa­hedral geometry. The mol­ecules are linked together via hydrogen bonds involving the water molecules. One of these is disordered equally over two positions

Bis[3-chloro-6-(3,5-dimethyl-1H-pyrazol-1-yl)picolinato]nickel(II) tetra­hydrate

In the title complex, [Ni(C11H9ClN3O2)2]·4H2O, the Ni atom is coordinated by four N atoms and two O atoms derived from two tridentate 3-chloro-6-(3,5-dimethyl-1H-pyrazol-1-yl)picolinate ligands. The cis-N4O2 donor set defines a distorted octa­hedral geometry. In the crystal structure, the complex and water mol­ecules are linked by O—H⋯O hydrogen bonds