Modification of the 5′ Terminus of Oligonucleotides for Attachment of Reporter and Conjugate Groups

Abstract

Reporter and conjugate groups can be added directly to the 5' terminus of oligonucleotides by appropriate modification. Conjugate groups can be used to increase the affinity of complementary strands, induce irreversible modification of target sequences, or enable sequences to recognize and permeate target cell membranes. This overview discusses the 5' modifications that can be used and strategies for the covalent attachment of ligands to the modified oligonucleotides. Step-by-step protocols for attachment of conjugate groups are given elsewhere in the series.

Arrays of graphene-quantum dots-supported DNA oligonucleotides as self-indicating porphyrin carriers

“…The cross-linking between the GQDs’ free amino groups and the phosphate groups from pre-denaturated 5′-Phos-DNA was performed in water at 60 °C in the presence of EDC/1-MeIm (Scheme S2, ESI†). 35,56…”

“…The cross-linking between the GQDs' free amino groups and the phosphate groups from pre-denaturated 5 0 -Phos-DNA was performed in water at 60 1C in the presence of EDC/1-MeIm (Scheme S2, ESI †). 35,56 After this synthetic step, the samples were not further dialysed, to ensure that the concentration of DNA was kept the same in each array. This decision was also taken by considering the high yields reported for EDC/1-MeIm-mediated DNA bioconjugation reactions (B79%) 57 and only after guaranteeing that none of these reagents had influence in the final stability of the arrays (exemplified in Fig.…”