Patent ID: 8394586

Claim:
A method for controlling the incorporation of nucleotides into a polynucleotide strand, comprising the steps of: (a) providing a nucleotide having a ribose or deoxyribose sugar moiety, wherein an enzymatically removable protecting group is attached to the 3′ oxygen atom of the ribose or deoxyribose sugar moiety of the nucleotide; (b) providing a first enzyme to incorporate the nucleotide into the strand, whereby the protecting group prevents incorporation of another nucleotide into the strand; and (c) providing a second enzyme to remove the protecting group to expose a 3′-OH group on the first nucleotide, thereby allowing incorporation of another nucleotide into the strand; (d) repeating steps (a) to (c) at least once; thereby controlling the incorporation of nucleotides into the strand; wherein the protecting group comprises an azido group or a disulfide.