Incorporation of a primary amine reactive functional group at specific sites within an oligonucleotide allows for subsequent post-synthesis conjugation of the oligo with a number of different affinity, reporter or protein labels, depending on the application. Such labels need to be reactive towards the incorporated functional group: for example, NHS esters or isothiocyanates will react with primary amines. This approach is often necessary where the desired label or tag is either not available as a phosphoramidite, or is sensitive or unstable to the conditions of oligonucleotide synthesis or deprotection. A common example is the attachment of a rhodamine dye using the TAMRA NHS ester. Functionally-derivatised oligos can also be covalently attached to surfaces such as glass slides or gold microspheres for use in various microarray or nanoelectronic applications.

Multi-addition amino-linkers can be added multiple times to an oligo either internally or at the end. This gives multiple sites for conjugation e.g. to maximise signal with in situ hybridization methods including FISH ⁽¹⁾

We offer non-nucleosidic and nucleosidic multi-addition amino linkers. Of the former, LK2535 and LK2563 are provided with either Fmoc or TFA protection, depending on your application. The nucleosidic products LK2557 and LK2558, have a dR moiety which sits directly into the natural sugar phosphate backbone with little disruption of the duplex, unlike the non-nucleosidic products, which means there is minimal effect on the Tm. In these products, the alpha anomer is nuclease resistant whereas the beta anomer is not.

Ref:

1. e.g. https://pubmed.ncbi.nlm.nih.gov/9301555/