How can you prevent oxidative damage of 7-deaza-dG during oligonucleotide synthesis?
RESPONSE:Non Aqueous Oxidation Using 10-Camphorsulfonyl-Oxaziridine Solutions of enantiomers of 10-camphorsulfonyl-oxaziridine in acetonitrile can be used for the non aqueous oxidation of phosphite triesters to phosphate triesters in oligonucleotide synthesis. This is especially helpful in the synthesis of oligonucleotides containing 7-deaza-dG which is susceptible to damage during the standard I2 catalyzed oxidation step. It was found that a 0.5 M solution of (1S)-(+)-(10-camphorsulfonyl)- oxaziridine in acetonitrile (0.5M CSO) was an effective oxidizer for DNA synthesis. Oxidation time course studies demonstrated that a 3 minute oxidation wait step was sufficient to completely oxidize the phosphite triester to the acid stable phosphate triester. A mixed base oligo synthesized using 0.5M CSO and a 3 min. oxidation wait was indistinguishable by HPLC analysis from the same oligo synthesized using 0.02M I2 oxidizer. Additionally oxidation using 0.5M CSO resulted in no distinguishable mod
