Peptide Nucleic Acids (PNA) Synthesis and Conjugation

Peptide nucleic acids (PNAs) are synthetic DNA/RNA analogs in which the nucleobases are attached to a neutral polyamide backbone rather than a sugar-phosphate backbone. Because of this structure, PNAs can bind DNA or RNA targets strongly and sequence-specifically, while offering high resistance to nucleases and proteases.

LifeTein supports both standard PNA oligomer synthesis and more advanced PNA formats, including peptide–PNA conjugates, fluorescently labeled PNAs, click-ready constructs, and modified monomer designs for research, diagnostic, and delivery-related applications.

When to Use PNA

• When stronger binding to DNA or RNA is needed than can typically be achieved with standard DNA or RNA analogs
• When enzymatic stability is important
• For PCR clamping or selective suppression of wild-type amplification
• For FISH probes and imaging applications under low-salt or challenging conditions
• For antisense, antigene, miRNA inhibition, or duplex invasion strategies
• For specialized delivery systems using peptide–PNA conjugates or click-enabled functionalization

For a broader decision guide, see When to Use PNA Instead of DNA or RNA.

Discuss Your PNA Project

You can contact us about sequence design, labels, peptide conjugation, click handles, solubility, or other PNA-specific requirements.

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PNA Formats and Modifications

LifeTein provides custom PNA oligo design, labeling, and conjugation, including unlabeled PNA oligomers, fluorescently labeled PNAs, peptide–PNA conjugates, and other specialized formats. Available labels and functional groups include fluorophores such as FAM, FITC, Alexa Fluor dyes, ATTO dyes, and cyanine dyes (Cy3, Cy5, Cy7); quenchers such as BHQ and Dabcyl; as well as biotin, maleimide, azide, alkyne handles, lipidation, and other custom modifications.

PNA Design Considerations

• PNA lengths of about 10–30 mers are used in many common applications.
• PNA melting temperatures are often higher than those of comparable DNA probes.
• Longer PNA sequences with high purine content may have reduced water solubility.
• Additional lysines or linkers such as AEEA, E linkers, or X linkers can improve solubility.
• Strong self-complementarity, hairpin-forming, inverse-repeat, or palindromic designs should generally be avoided.

Selected PNA Products and Probe Formats

For stocked or semi-standard examples, see PNA probes, inhibitors, and selected products.

PNA FISH Probe Examples

PNA Applications

• Microarrays and biosensors
• PCR clamping and artificial restriction strategies
• Imaging probes and FISH
• Antisense and antigene studies
• miRNA inhibitors
• Double-strand DNA invasion and capture
• PNA-assisted DNAzyme and PNAzyme concepts
• Lipid nanoparticle and delivery-related work

CPP-PNA Examples

Case Study: Confidential PNA–Peptide Conjugate with Pseudoisocytosine and Click-Ready Handle

To illustrate the complexity of our PNA platform, the following anonymized construct represents a confidential PNA–peptide conjugate format:

H-PKKKRKVKK-{TxJTxxJJ}-linker-{CxxxTCxxxT}-x-K(N₃)-NH₂

Key features of this construct

• A cell-penetrating peptide sequence derived from nuclear localization or delivery motifs
• PNA domains containing pseudoisocytosine (J) to improve triplex stability
• A flexible linker to reduce steric constraints during hybridization
• A click-ready Lys(N₃) handle for site-specific downstream conjugation

Application relevance

• Synthesis of difficult monomers such as J (pseudoisocytosine)
• Construction of advanced peptide–PNA hybrids
• Formats suitable for gene regulation, antisense studies, and targeted delivery research

Case Study: Fluorescent PNA with Azido Handle

This case study shows a PNA synthesis with a fluorescent Cyanine Dye Cy5 modification at the N-terminus and an azido group at the C-terminus for downstream click chemistry.

Cys(Cy5)-{XXXXXX}-Lys(N3)-NH2, where X represents A, T, G, or C monomers. Fmoc-Lys(N3)-OH was used to introduce a side-chain azido group that remains suitable for selective downstream modification.

Related PNA Resources

• When to Use PNA Instead of DNA or RNA
• Custom PNA Oligo Design, Labeling, and Conjugation
• PNA Probes, Inhibitors, and Selected Products
• PNA-Assisted DNAzyme Systems and PNAzyme Concepts