6-Azido-D-lysine HCl

Product Information

Stable and Bioorthogonal Protein Labeling with D-Amino Acid Technology

6-Azido-D-lysine ((R)-2-Amino-6-azidohexanoic acid hydrochloride) is a synthetic unnatural D-amino acid derivative of lysine carrying an azide group. This reagent enables site-specific protein modification and bioorthogonal labeling via Click Chemistry (SPAAC or CuAAC) or Staudinger ligation under mild conditions.

Incorporation Methods

• Genetic Code Expansion: Engineered tRNAs (based on prokaryotic tRNAs) recognize amber codons (usually UAG) and incorporate 6-Azido-D-lysine at a defined position during biosynthesis^[1].
• Solid Phase Peptide Synthesis (SPPS): Allows chemical incorporation at any position in the peptide sequence for versatile functionalization.

After incorporation, the azide moiety reacts selectively with alkyne-modified partners (DBCO, BCN, PEGs, dyes) or P(III)-containing reagents, enabling efficient conjugation without side reactions.

Why choose 6-Azido-D-lysine?

Traditional NHS ester chemistry reacts with primary amines (e.g., lysines), leading to:

• Non-specific labeling at multiple sites
• Requires basic pH (8–9) and overnight reactions
• Risks protein degradation and structural changes

In contrast, azide-based labeling with 6-Azido-D-lysine offers:

• Site-specific modification at the planned position
• Fast reactions at neutral pH with high yields
• Preserves tertiary structure
• Fully biorthogonal, no interference with native functional groups
• Lower reagent consumption and atom-economic click chemistry for cost-effective, eco-friendly workflows
• Unique Benefits of D-Amino Acid Incorporation

Unique Benefits of D-Amino Acid Incorporation

The usage of a D-amino acid instead of an L-amino azide for introduction of the labels has several influences on the peptide.

1. Increased stability: Peptides containing a D-amino acid are more stable than only L-amino acids containing peptides because proteases and peptidases can not break a bond involving a D-amino acid.
2. Structural Variations: D-amino acids alter peptide folding (e.g., prevent α-helix formation), enabling novel structural designs for research and drug development.

Key Advantages of 6-Azido-D-lysine:

1. Integrity of tertiary structure: SPAAC and CuAAC reactions can be performed at neutral pH and in short reaction times. Therefore, the chemical modification of your peptide/protein is possible without the risk of the target biomolecule degrading.
2. Fast & Efficient Click Reactions: The used click chemistry forms highly stable triazole bonds with all alkynes or alkyne derivates which can be used for strain-promoted alkyne-azide cycloaddition in short reaction time.
3. Specific labeling: Since 4-Azido-L-homoalanine is incorporated into your peptide/protein at a precisely defined position, highly specific labeling at this position is possible.
4. Increased stability: Peptides including D-amino acids are more stable against enzymatic degradation.

This reagent is used for:

• Protein/Peptide labeling
• Solid phase peptide synthesis (SPPS)
• Antibody labeling
• Antibody modification for the synthesis of antibody-drug conjugates (ADCs)
• Linking targeting moieties to peptides/proteins

LITERATURE

[1] Incorporating unnatural amino acids into recombinant proteins in living cells, Mitra, N., 2013, Materials and Methods, 3(204), 1.

https://doi.org/10.13070/mm.en.3.204

Synthesis of biologically active nickelocenyl–amino acid conjugates using 1,3-dipolar cycloaddition click reactions, M. A. Raza et al., 2017, Russ. J. Gen. Chem., Vol. 87, p. 2678–2683.

https://doi.org/10.1134/S107036321711024X

Chemically Induced Cell Wall Stapling in Bacteria, S. L. Rivera et al., 2021, Cell Chemical Biology, Vol. 28(2), p. 213-220.

https://doi.org/10.1016/j.chembiol.2020.11.006

Systematic Assessment of Accessibility to the Surface of Staphylococcus aureus, N. J. Ferraro et al., 2021, ACS Chem. Biol., Vol. 16(11), p. 2527–2536.

https://doi.org/10.1021/acschembio.1c00604