MadSci Network: Cell Biology

Re: Ammonia and Ureas' affect on DNA?

Date: Tue Sep 5 12:11:21 2000
Posted By: Elena Rodriguez, Grad student, Molecular and Cell Biology, University of California, Berkeley
Area of science: Cell Biology
ID: 962421796.Cb

I apologize for taking so long to answer the question.

Denaturing agents such as urea and formamide (HCONH2) are called chaotropic 
agents because they tend to disrupt water's ability to solvate DNA's 
negatively charged phosphate groups.  The negative charges, then, repel each 
other more strongly and induce a "rodlike" conformation of the DNA.
(the C2' endo configuration of the ribose ring is even more exaggerated and 
the phospates are even  further apart) 

In order to oppose this destabilizing affect, I would suggest increasing the 
ionic strength of the solvent (salt), so that positively charged monovalent 
ions can quench the negative charges.

Thanks for being so patient,
Elena Rodriguez

Current Queue | Current Queue for Cell Biology | Cell Biology archives

Try the links in the MadSci Library for more information on Cell Biology.

MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci

MadSci Network,
© 1995-2000. All rights reserved.