Carina Frauer

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Protein conformation is critically linked to function and often controlled by interactions with regulatory factors. Here we report the selection of camelid-derived single-domain antibodies (nanobodies) that modulate the conformation and spectral properties of the green fluorescent protein (GFP). One nanobody could reversibly reduce GFP fluorescence by a(More)
Recent discovery of 5-hydroxymethylcytosine (5hmC) in genomic DNA raises the question how this sixth base is recognized by cellular proteins. In contrast to the methyl-CpG binding domain (MBD) of MeCP2, we found that the SRA domain of Uhrf1, an essential factor in DNA maintenance methylation, binds 5hmC and 5-methylcytosine containing substrates with(More)
Several mammalian proteins involved in chromatin and DNA modification contain CXXC zinc finger domains. We compared the structure and function of the CXXC domains in the DNA methyltransferase Dnmt1 and the methylcytosine dioxygenase Tet1. Sequence alignment showed that both CXXC domains have a very similar framework but differ in the central tip region.(More)
DNA methylation and histone modifications play a central role in the epigenetic regulation of gene expression and cell differentiation. Recently, Np95 (also known as UHRF1 or ICBP90) has been found to interact with Dnmt1 and to bind hemimethylated DNA, indicating together with genetic studies a central role in the maintenance of DNA methylation. Using in(More)
Gene expression is regulated by DNA as well as histone modifications but the crosstalk and mechanistic link between these epigenetic signals are still poorly understood. Here we investigate the multi-domain protein Uhrf2 that is similar to Uhrf1, an essential cofactor of maintenance DNA methylation. Binding assays demonstrate a cooperative interplay of(More)
We present a simple, non-radioactive assay for DNA methyltransferase activity and DNA binding. As most proteins are studied as GFP fusions in living cells, we used a GFP binding nanobody coupled to agarose beads (GFP nanotrap) for rapid one-step purification. Immobilized GFP fusion proteins were subsequently incubated with different fluorescently labeled(More)
Pyrrolysine (Pyl), the 22nd naturally encoded amino acid, gets acylated to its distinctive UAG suppressor tRNA(Pyl) by the cognate pyrrolysyl-tRNA synthetase (PylRS). Here we determine the RNA elements required for recognition and aminoacylation of tRNA(Pyl) in vivo by using the Pyl analog N-epsilon-cyclopentyloxycarbonyl-l-lysine. Forty-two Methanosarcina(More)
Investigation of single RNA molecules using fluorescence resonance energy transfer (FRET) is a powerful approach to investigate dynamic and thermodynamic aspects of the folding process of a given RNA. Its application requires interdisciplinary work from the fields of chemistry, biochemistry, and physics. The present work gives detailed instructions on the(More)
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