site directed mutagensis - (Oct/26/2006 )

hi
I am doing site directed mutagensis. My primers are quite long as I am doing loop mutations on protein strcuture. So I am doing polyalanine subsitution. after PCR, I ran the gel to see whether I have got some PCR products along with control template DNA.BUt oh no.. no band . I can see the control but no band in PCR product samples...I am stunned!!! what can be done to see ,,yes PCR is successful. help me out please..

Can you let us know the PCR conditions you ran for the protocol? Also, are you using the SDM protocol from Stratagene or another source??