3’-Amino-Modifier CPGs, containing amino groups protected with the base-labile Fmoc group, are designed to functionalize the 3’-terminus of the target oligonucleotide by the introduction of a primary amine. In an alternative approach, the nitrogen destined to become the 3’-amino group is included in a phthalimide (PT) group which is attached to the support through an amide group attached to the aromatic ring. This simple linkage is very stable to all conditions of oligonucleotide synthesis and contains no chiral center. Using an extended ammonium hydroxide treatment (55°C for 17 hours), the cleavage of the amine from the phthalimide is accomplished along with the deprotection of the oligonucleotide. ABI-style columns are supplied unless otherwise requested.
The 3’-Thiol-Modifier S-S CPG supports are used to introduce 3’-thiol linkages with three and six atom spacers into oligonucleotides. 3’-Dithiol Serinol CPG is used to introduce a dithiol group at the 3’-terminus. In conjunction with Dithiol Serinol Phosphoramidite, it is simple to produce oligonucleotides with multiple thiol groups at the 3’ terminus, which is ideal for conjugation to gold surfaces. With Glyceryl CPG the 3’-terminus of an oligonucleotide is readily oxidized by sodium periodate to form a 3’-phosphoglycaldehyde. The aldehyde may be further oxidized to the corresponding carboxylic acid. Either the aldehyde or the carboxylate may be used for subsequent conjugation to amine-containing products.
3’-Amino-Modifier C6 dC CPG and 3’-Amino-Modifier C6 dT CPG replace a dC and T, respectively, at the 3’-terminus. These products allow convenient labeling at the 3’ without blocking the terminus from desired enzymatic activity.