biotin-Ahx-RKKRRQRRR-NH2

RKKRRQRRR is a 9-amino acid peptide derived from the HIV-1 Tat protein (trans-activator of transcription). It is widely recognized as a cell-penetrating peptide (CPP) that can translocate across cell membranes and facilitate the intracellular delivery of biomolecules such as nucleic acids, proteins, and nanoparticles.

Upon binding to NRP-1, RPARPAR activates an endocytic pathway that enhances the permeability of blood vessels, allowing for deeper tissue penetration. This mechanism is particularly valuable in targeting tumor vasculature, as it enables the delivery of therapeutic agents directly into tumor tissues.

Functional & Experimental Applications

• Intracellular Delivery: Conjugation to proteins, peptides, DNA, RNA, or small molecules for delivery into mammalian cells.
• Gene Therapy & Nucleic Acid Research: Facilitates transfection and siRNA/shRNA delivery.
• Therapeutic Development: Used in experimental therapeutics to transport drugs or imaging agents into target cells.
• Fluorescent or FAM Conjugates: Modified versions (e.g., FAM-RKKRRQRRR) enable visualization of cellular uptake.

Mechanism of Action: Cell-penetrating via electrostatic interactions with cell surface GAGs, endocytosis, and direct translocation

biotin-Ahx-RKKRRQRRR-NH2 is a synthetic research peptide in the HIV-1 Tat(49-57) cell-penetrating peptide category. The arginine-rich HIV-1 Tat basic-domain sequence RKKRRQRRR corresponds to Tat residues 49-57 and is a classic cell-penetrating peptide. Published structure-function work established this short basic domain as a transport sequence and demonstrated that the arginine/guanidinium-rich character is central to translocation. Biotin/Ahx modification creates a labeled construct whose uptake should be validated independently.

• cell-penetrating peptide uptake studies
• cargo-delivery experiments
• membrane/translocation research
• biotinylated Tat binding or capture assays

The exact supplied sequence and modification state should be used when interpreting published results. Activity reported for a parent peptide, labeled derivative, formulation, species variant, or related analog should not automatically be assigned to this construct.

1. Design and evaluation of arginine-rich Tat-derived molecular transporters
2. Tat peptide-mediated cellular delivery: back to basics