E3 ubiquitin-protein ligase RNF43 (11-19(20))

E3 ubiquitin-protein ligase RNF43 (11-19(20)) is a synthetic peptide fragment derived from the RNF43 protein, an important E3 ubiquitin ligase involved in the regulation of Wnt signaling pathways. This peptide corresponds to amino acid residues 11 to 19 (with possible extension to residue 20) of the RNF43 sequence, a region implicated in protein-protein interactions and post-translational modification processes. Its biochemical relevance lies in its utility as a molecular tool for dissecting the structural and functional aspects of RNF43-mediated ubiquitination, a process critical for the modulation of cellular signaling, protein turnover, and homeostasis. Researchers employ this peptide to elucidate the mechanistic underpinnings of RNF43 function, particularly in contexts where precise control or mimicry of native protein segments is required for in vitro and in vivo studies.

Peptide mapping: The synthetic RNF43 (11-19(20)) fragment serves as an essential standard in peptide mapping experiments, enabling researchers to accurately identify and characterize RNF43-derived peptides in complex biological samples. By comparing the retention time, mass spectra, and fragmentation patterns of this synthetic peptide with those observed in proteolytic digests, scientists can confirm the presence, integrity, and post-translational modifications of RNF43 in various experimental systems. This approach is particularly valuable in mass spectrometry-based proteomics, where precise peptide standards are necessary for robust protein identification and quantification.

Protein-protein interaction studies: The defined sequence of the RNF43 (11-19(20)) peptide allows for detailed investigations into the binding interfaces and interaction partners of the RNF43 protein. By employing this fragment in pull-down assays, surface plasmon resonance, or isothermal titration calorimetry, researchers can probe the affinity and specificity of RNF43's interactions with regulatory proteins, substrates, or inhibitors. Such studies are instrumental in mapping the critical residues required for functional complex formation and in designing competitive inhibitors or mimetics to modulate RNF43 activity in cellular models.

Antibody production and validation: The RNF43 (11-19(20)) peptide is widely utilized as an immunogen or as a control antigen in the development and validation of antibodies targeting the N-terminal region of RNF43. By conjugating this sequence to carrier proteins or using it directly in ELISA and Western blot assays, scientists can generate and rigorously test antibody specificity and sensitivity. High-quality antibodies raised against this peptide facilitate the detection, quantification, and localization of RNF43 in a range of biological samples, supporting studies on protein expression, distribution, and turnover.

Enzyme substrate studies: As a representative epitope of the RNF43 protein, this peptide fragment is employed as a substrate in in vitro ubiquitination assays and related enzymatic studies. Researchers use it to assess the catalytic activity of E3 ligases, deubiquitinases, or other modifying enzymes that interact with RNF43 or its motifs. By monitoring the modification of the synthetic peptide under controlled conditions, it is possible to dissect the sequence requirements and mechanism of enzyme-substrate recognition, contributing to a deeper understanding of post-translational modification dynamics.

Structural and functional analysis: Incorporating the RNF43 (11-19(20)) peptide into structural biology workflows enables the exploration of conformational features and functional motifs relevant to the full-length RNF43 protein. Through techniques such as NMR spectroscopy, X-ray crystallography, or molecular modeling, this peptide can provide atomic-level insights into the folding, dynamics, and interaction surfaces of the RNF43 N-terminal region. Such structural information is invaluable for guiding mutagenesis studies, rational drug design, and the development of molecular probes that target RNF43-mediated signaling pathways.

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