Inverted-dT (Figure 1) can be introduced at the 3’-end of an oligonucleotide to create a 3’-3’ linkage that stops DNA polymerase from further extending the DNA sequence. Additionally, inverted-dT protects the oligonucleotide from 3’ exonuclease cleavage.
Figure 1. Structure of Inverted-dT (R = sequence).
metabion offers inverted-dT in its DNA portfolio: