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.
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.