how does rna precipitate in LiCl solution ? - (Oct/23/2010 )

HI all

I have been isolating rna manually from leaves of arabidopsis plants using phenol/sds method and using licl as additional step for precipitation of rna. I had to precipitate the rna in 2M Licl in 4C but i did it at -20C for overnight . I wonder how rna precipiates in -20C when the solution became ice.


Please help.

Lithium and other cations help to "shield" or neutralize negative charges on RNA/DNA. Time and temperature probably only effect yield. o/n precipitation at either temperature probably isn't necessary. More discussion here:

http://www.madsci.org/posts/archives/2000-07/965055056.Mb.r.html

http://www.ambion.com/techlib/tb/tb_160.html