NLS (PKKKRKV) is a peptide derived from the simian virus 40 large tumor antigen (SV40 large T antigen), as a method to enhance nuclear entry in the field of gene transfer research.
CAT No: R1561
CAS No:95088-49-6
Synonyms/Alias:NLS (PKKKRKV);95088-49-6;L-Valine, L-prolyl-L-lysyl-L-lysyl-L-lysyl-L-arginyl-L-lysyl-;NLS PKKKRKV;Pro-Lys-Lys-Lys-Arg-Lys-Val;SCHEMBL5402328;HY-P1876;(2S)-2-[[(2S)-6-amino-2-[[(2S)-2-[[(2S)-6-amino-2-[[(2S)-6-amino-2-[[(2S)-6-amino-2-[[(2S)-pyrrolidine-2-carbonyl]amino]hexanoyl]amino]hexanoyl]amino]hexanoyl]amino]-5-(diaminomethylideneamino)pentanoyl]amino]hexanoyl]amino]-3-methylbutanoic acid;DA-56206;PD159285;CS-0097312;(3S,6S,9S,12S,15S,18S)-3,6,9,15-Tetrakis(4-aminobutyl)-12-(3-guanidinopropyl)-18-isopropyl-1,4,7,10,13,16-hexaoxo-1-((S)-pyrrolidin-2-yl)-2,5,8,11,14,17-hexaazanonadecan-19-oic acid;
NLS PKKKRKV is a synthetic peptide sequence representing the classical nuclear localization signal (NLS) derived from the SV40 large T-antigen. As a short, highly basic peptide motif, it is recognized by the importin α/β nuclear transport machinery, facilitating the active import of macromolecules into the cell nucleus. The PKKKRKV sequence is widely used in molecular and cellular biology as a prototypical NLS, making it a valuable tool for probing nucleocytoplasmic transport mechanisms, engineering nuclear-targeted biomolecules, and studying the regulation of nuclear import pathways. Its well-characterized biochemical properties and robust nuclear import activity have established it as a standard reference for nuclear localization studies and as a functional tag in a variety of research applications.
Nuclear transport studies: The PKKKRKV peptide is routinely employed in research investigating the molecular mechanisms of nuclear import. By conjugating this NLS motif to proteins, nucleic acids, nanoparticles, or other macromolecules, researchers can systematically examine the efficiency and specificity of nuclear translocation in different cell types and experimental conditions. The peptide's defined sequence and high affinity for importin receptors make it a model system for dissecting the steps and regulatory factors involved in nucleocytoplasmic trafficking, enabling detailed analyses of transport kinetics, cargo recognition, and the impact of cellular signaling pathways on nuclear import.
Protein engineering and fusion constructs: Incorporation of the PKKKRKV sequence into recombinant proteins or synthetic constructs is a widely adopted strategy for directing exogenous or engineered molecules to the nucleus. By fusing the NLS to the N- or C-terminus of target proteins, scientists can achieve efficient nuclear localization, facilitating functional studies of nuclear proteins, transcription factors, genome-editing enzymes, or reporter constructs. This approach is integral to dissecting nuclear processes, such as gene expression regulation, chromatin remodeling, and DNA repair, by ensuring that the molecular tools or probes of interest are correctly compartmentalized within the cell.
Live-cell imaging and tracking: The NLS peptide serves as a key component in live-cell imaging assays designed to monitor nuclear import dynamics in real time. By labeling the PKKKRKV motif or NLS-tagged cargo with fluorescent dyes or fusion proteins, researchers can visualize and quantify the intracellular trafficking and nuclear accumulation of molecules. These imaging-based applications provide critical insights into the temporal and spatial regulation of nuclear import, the responsiveness of transport pathways to cellular stress or signaling cues, and the effects of mutations or inhibitors on nucleocytoplasmic exchange.
Delivery system development: The use of the PKKKRKV nuclear localization signal extends to the design and optimization of delivery systems for nucleic acids, proteins, or therapeutic agents that require nuclear access for activity. By integrating the NLS motif into delivery vehicles such as nanoparticles, liposomes, or viral vectors, scientists can enhance the nuclear targeting efficiency of their cargo, supporting studies on gene regulation, genome editing, and the development of advanced molecular tools. The functionalization of delivery systems with this peptide motif is critical for achieving precise subcellular localization and for evaluating the performance of nuclear delivery strategies in vitro.
Biochemical assays and importin interaction studies: The PKKKRKV sequence is frequently utilized in biochemical assays that characterize the binding interactions between nuclear localization signals and importin receptors. By serving as a defined ligand, it enables quantitative binding studies, competition assays, and the screening of small molecule modulators that influence nuclear import. These applications are instrumental in elucidating the molecular determinants of NLS recognition, mapping the specificity of importin isoforms, and advancing the understanding of nuclear transport regulation at the molecular level.
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