Increase the melting temperature of short, AT-rich primers and probes

Super T®—a duplex stabilizing, modified dT base

Add this modified base to increase the melting temperature (Tm) of primers and probes. It is especially useful when you need to work with short, A-T rich sequences.

Dec 29, 2015

Revised/updated Aug 24, 2016

Quick facts

Availability: DNA and RNA
5', internal, and 3'
100 nmol to large scale
Purification: Standard desalt or HPLC
Ordering (modification codes):
5Super-dT/, /iSuper-dT/, /3Super-dT/

Super T (5-hydroxybutynyl-2'-deoxyuridine; Figure 1) is a modified dT base that can be included in oligonucleotide primer and probe sequences to stabilize their hybridization. Super T base-pairing with dA during primer or probe hybridization provides an ~2°C increase in melting temperature (Tm) per Super T insertion. This Tm increase can be essential when working with short primers or probes that are AT rich.

The Super T modified base is extended normally by polymerases, including Taq polymerase.


Figure 1. Structure of 3′–3′ or 5′–5′ reversed linkages.

How to order

To include Super T bases within your oligo, enter the IDT ordering symbol (/5Super-dT/, or /iSuper-dT/, or /3Super-dT/) in the desired location within your sequence. You can request Super T modified oligonucleotides with standard desalt or HPLC purification.