Biotin-dT can replace dT residues within the oligonucleotide sequence. 5'-Biotin phosphoramidite can be added ONLY ONCE to the 5'-terminus of an oligonucleotide. However, the DMT group on the biotin can be used in RP cartridge and HPLC purification techniques. PC Biotin is a photocleavable 5'-biotin phosphoramidite. BiotinTEG CPG and Protected BiotinLC Serinol CPG are designed for the direct synthesis of oligonucleotides containing biotin at the 3' terminus.
Desthiobiotin is a biotin analogue that exhibits lower binding to biotin-binding proteins such as streptavidin. This biotin analogue is lacking the sulfur group from the molecule and has a dissociation constant (Kd) several orders of magnitude less than biotin/streptavidin. As a result, biomolecules containing desthiobiotin are dissociated from streptavidin simply in the presence of buffered solutions of biotin. We offer desthiobiotinTEG phosphoramidite and the corresponding CPG.
Coupling: 15 minute coupling recommended
Deprotection: No changes needed from standard method recommended by synthesizer manufacturer.
Refrigerated storage, maximum of 2-8°C, dry
The table below show pack size data and, for solutions, dilution and approximate coupling based on normal priming procedures.
1. Biotin dT will not affect the ability of kinase to phosphorylate at the 5'-terminus.2. The presence of Biotin-dT within an oligonucleotide does not affect hybridization relative to the same oligo containing dT(1). The biotin resides in the major groove of the formed double-stranded DNA and is readily available for binding to avidin or streptavidin.||REFERENCE(S): (1) J. Telser, K.A. Cruickshank, L.E. Morrison, and T.L. Netzel, J. Am. Chem. Soc., 1989, 111, 6966-6976. , ||
No. However, this can be produced on the synthesizer by adding to the 5'- terminus first 5'-thiol-modifier C6 S-S (10-1936) followed by BioTEG phosphoramidite (10-1955). This should generate a biotinylated primer with a long spacer arm containing the disulfide linkage which can be cleaved later with DTT.||
A colorimetric assay for biotin can be quite effective. The color results from the reaction of biotin with p-dimethylaminocinnamaldehyde in the presence of sulfuric acid.1. Spot 0.2 A260 units of biotinylated oligonucleotide on a silica gel TLC plate.2. Dry the plate.]3. Spray with a solution of 2% p-dimethylaminocinnamaldehyde (Sigma), 2% conc. sulfuric acid in ethanol.4. Heat the plate and the presence of biotin will be indicated by the formation of a pink spot.Since the intensity of the biotin spot is quite low, it is prudent to compare with an unlabelled oligonucleotide similarly treated.