SSCP primer design based on single-strand DNA structure predicted by a DNA folding program.

To predict alterations in single-strand DNA mobility in non-denaturing electrophoretic gels, Zuker's RNA folding program was modified. Energy files utilized by the LRNA RNA folding algorithm were modified to emulate folding of single-strand DNA. Energy files were modified to disallow G-T base pairing. Stacking energies were corrected for DNA thermodynamics. Constraints on loop nucleotide sequences were removed. The LRNA RNA folding algorithm using the DNA fold energy files was applied to predict folding of PCR generated single-strand DNA molecules from polymorphic human ALDH2 and TPH alleles. The DNA-Fold version 1.0 program was used to design primers to create and abolish SSCP mobility shifts. Primers were made that add a 5' tag sequence or alter complementarity to an internal sequence. Differences in DNA secondary structure were assessed by SSCP analysis and compared to single-strand DNA secondary structure predictions. Results demonstrate that alterations in single-strand DNA conformation may be predicted using DNA-Fold 1.0.