DNA is Held Together by a Watery Environment

  • Thread starter jedishrfu
  • Start date
10,937
4,448
 

Ygggdrasil

Science Advisor
Insights Author
Gold Member
2,920
2,060
What were scientists wrong about? We have already known this for over half a century:

Herskovits. Nonaqueous solutions of DNA: Factors determining the stability of the helical configuration in solution. Arch. Biochem Biophys 97: 474 (1962)

Abstract:
The disorganization of the aqueous helical configuration of deoxyribonucleic acid (DNA) by a number of structurally related organic solvents has been investigated. In all the solvents investigated, denaturation is accompanied by 35–50% increase in absorbance (at 259 mμ) and a decrease in optical rotation (at 436 mμ) of 200–350 °. The following observations have been made: (a) The effectiveness of the denaturant increases with both chain length and increasing hydrocarbon content. Thus ethyl and propyl alcohols were found to be more effective than methanol. (b) The alkyl-substituted solvents N,N′-dimethylformamide, dimethyl sulfoxide, and tetramethylurea are the most effective denaturants among the various solvents employed. The midpoints of the denaturation transition due to these solvents in the presence of 1–5 × 10−2M salt, range from 19 to 27 mole % (57–62 vol.%), and the changes produced in optical rotation (at 436 mμ) upon denaturation are of the order of −300 to −350 °. (c) N,N′-dimethylformamide is a more effective DNA denaturant than formamide. (d) Increasing the hydroxyl content of the solvent, on the other hand, had no significant effect; the denaturation midpoints in methanol-water and ethylene glycol-water mixtures (in the presence of 0.5–5 × 10−2M salt) occur at 80 ± 1 mole % (90 ± 2 vol.%) of the nonaqueous component. These observations demonstrate the importance of hydrophobic forces and argue against the assignment of the stability of the aqueous configuration of DNA solely to hydrogen bonds.
(emphasis mine)

The fact that the hydrophobic effect and base stacking are key to the stability of double stranded DNA has been demonstrated in numerous experiments, including a classic study from over two decades ago, where chemists synthesized an artificial DNA base pair that works without hydrogen bonding:

Matray and Kool. Selective and Stable DNA Base Pairing without Hydrogen Bonds. J Am Chem Soc 120:6191 (1998)
 

Want to reply to this thread?

"DNA is Held Together by a Watery Environment" You must log in or register to reply here.

Related Threads for: DNA is Held Together by a Watery Environment

Replies
26
Views
4K
  • Posted
2
Replies
38
Views
15K
  • Posted
Replies
7
Views
10K
  • Posted
Replies
1
Views
2K
  • Posted
Replies
19
Views
29K
Replies
1
Views
1K
  • Posted
Replies
3
Views
2K
  • Posted
Replies
7
Views
4K

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving

Hot Threads

Top