Glen Report 33-17: Technical Snippets

Why are phosphoramidites and synthesis supports with freezer storage conditions shipped at ambient temperature rather than with dry ice?

It is because cold shipping is not necessary when shipping these products. The bulk of these products are shipped at ambient temperature with priority shipping, no ice packs nor dry ice, and this is rarely an issue. These products are generally very stable and are not like proteins that will irreversibly denature beyond a certain temperature. The recommended storage temperatures are for long term storage, and a few days at ambient temperature do not impact product quality whatsoever. There is a small selection of products, less than 10, that are more susceptible to short term elevated temperatures, and those products are shipped with ice packs.

Products: All products that require freezer storage.



How does one synthesize an oligonucleotide with a 3’-inverted dT?

The synthesis is accomplished with a reverse synthesis dT support and standard phosphoramidites. An inverted dT modification at the 3’-end is a convenient way to reduce susceptibility to 3’-exonucleases as well as prevent DNA polymerase extension. By starting with a reverse dT support and then performing standard 3’ to 5’ synthesis, a 3’-3’ linkage is created at the beginning (Figure 1).

Product: dT-5’-CPG (20-0302)

Figure 1

Figure 1. Formation of a 3’-inverted dT