Cys-TAT(47-57)

Cys-TAT(47-57) is a synthetic peptide comprising the trans-activator of transcription (TAT) protein transduction domain from residues 47 to 57, with an N-terminal cysteine residue. This peptide is widely recognized for its exceptional ability to facilitate cellular uptake, attributed to the TAT domain derived from the HIV-1 virus. The inclusion of a cysteine at the N-terminus enables site-specific conjugation, expanding its versatility for a range of biochemical and molecular biology applications. Its unique structure and functional attributes make it an invaluable tool in peptide research, molecular delivery systems, and studies involving cell-penetrating peptides.

Cellular Delivery Studies: Cys-TAT(47-57) serves as a robust model for investigating cell-penetrating peptides and their mechanisms of translocation across biological membranes. Researchers utilize it to evaluate the efficiency and pathways of peptide-mediated cellular entry, providing insights into endocytic and non-endocytic transport mechanisms. Its well-characterized sequence allows for systematic studies of structure-activity relationships, helping to unravel how peptide modifications influence intracellular delivery.

Conjugation and Bioconjugate Design: The presence of the N-terminal cysteine residue makes this peptide highly amenable to site-specific conjugation strategies, such as thiol-maleimide coupling. Scientists frequently employ Cys-TAT(47-57) to covalently attach functional cargos, including proteins, nucleic acids, fluorescent probes, or nanoparticles, for targeted intracellular delivery. This application enables the development of advanced bioconjugates for probing cellular processes, imaging, and functional assays.

Intracellular Targeting and Functional Studies: By utilizing the TAT domain's inherent membrane-translocating capability, the peptide is often employed to deliver bioactive molecules directly into the cytoplasm or specific subcellular compartments. This approach is instrumental in dissecting the intracellular effects of various cargos, facilitating studies on protein-protein interactions, signal transduction, and gene regulation within living cells. The peptide thus enables precise manipulation of intracellular environments for experimental purposes.

Peptide Modification and Structure-Activity Analysis: Cys-TAT(47-57) is extensively used as a template for the design and synthesis of modified peptides aimed at optimizing cellular uptake or altering biodistribution. Researchers can systematically substitute amino acids or append chemical groups to the peptide backbone, enabling detailed structure-activity relationship studies. These investigations contribute to the rational design of next-generation cell-penetrating peptides with improved specificity, efficiency, or reduced cytotoxicity.

Analytical and Quantitative Uptake Assays: The peptide's defined sequence and reactivity make it a valuable standard in quantitative uptake assays and analytical method development. By labeling the peptide with various reporter groups, scientists can calibrate and validate fluorescence-based, radiometric, or mass spectrometric assays that monitor peptide internalization. This application supports the establishment of robust, reproducible methods for assessing cellular delivery efficiency in diverse experimental systems.

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