ds Sequencing Qiagen-prep Plasmids-Help!

[Carlisle Landel]

We can ds sequence plasmid DNA made by the STET boiling miniprep
DNA any time we want.  

When we try the same protocol on DNA purified using a Qiagen maxi
prep, it doesn't work, ie, no bands at all.  DNA that is too pure
to sequence seems a little strange.  I thought maybe that it was
all supercoiled, so that it wouldn't be a good substrate for the
polymerase in vitro, but cutting the plasmid to linearize it gave
only the slightest improvement (I can now see bands, but they are
*very* faint).

Does anybody have any ideas about how to fix this?  It seems silly
to do a bunch of minipreps when in theory one big maxiprep should
give you a life time supply of DNA, but that is the fix we have been
reduced to using.

Thanks

Carlisle Landel