formamide and DNA denaturation - (Jun/19/2007 )

Can someone provide me with a protocol to use formamide to denature Chromosomal DNA of E. coli. I was trying to use boiling but I realized that the high temperature breaks the DNA backbone (The DNA looks completely smeared in a gel)

formamide is just used to dicrease the denaturing temp of DNA 42 instead of 95 to ebulition.
denature by temperature without formamide (100°C for 5-10min)
if you insist to use formamide incubate at 42-50°C max
goooood luck