Suggestions for oligo modifications - (May/29/2006 )

I need suggestion for a modification that I can put at the 3' end of an oligo so that it will not be extensible. Will a phosphate work? The company I order my oligos from do not offer ddNTPs so I am a little stuck as to what to do.

Thanks

why dont you just dephosporylate? will prevent any extension of the oligo

extension of oligo is done from 3' OH terminus. So dephosphorylation of the 5' will not help

doh! sorry

A 3' phosphate will prevent extension, but is somewhat unstable. Best would be a dideoxy. You could add a 3' ddNTP with terminal transferase and the appropriate ddNTP.

Thanks for the responses. I've ordered my oligo with a 3' phoshpate, so we'll see how it works. The company doesn't offer ddNTPs or that's what I would have gon with.

hi
i was reading roche catalog and though about your post, and they sold ddNTP.