Tm of oligopurine/oligopyrimidine hybrids

[Olav Hungnes]

My question is probably a close relative to the oligoT 
Tm question posted here yesterday:
I'm designing a PCR where one of the primers will contain the polypurine 
tract of HIV-1. (ctttttAAAAGAAAAGGGGGGactg). Programs like OLIGO tell me 
that the Tm should be about 57 oC. Does anybody know if the one-purine/one 
pyrimidine-strand constellation will raise the Tm above the value 
calculated by the standard equations? For the viral 
rOligopurine/dOligopyrimidine situation (during reverse 
transcription/plus-strand priming) this is believed to be the case.

Olav

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Olav Hungnes                 olav.hungnes at embnet.uio.no
National Institute               Phone  (+47)22042200
of Public Health                 FAX    (+47)22353605
Oslo, NORWAY
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