Journal
BIOCHEMISTRY
Volume 54, Issue 6, Pages 1364-1370Publisher
AMER CHEMICAL SOC
DOI: 10.1021/bi5014722
Keywords
-
Categories
Funding
- National Science Foundation under Mississippi EPSCoR [EPS-0903787]
- National Institutes of Health [R15 CA173667-01A1]
- Office Of The Director
- EPSCoR [0903787] Funding Source: National Science Foundation
Ask authors/readers for more resources
The four-stranded i-motif (iM) conformation of cytosine-rich DNA is important in a wide variety of biochemical systems ranging from its use in nanomaterials to a potential role in oncogene regulation. An iM is stabilized by acidic pH that allows hemiprotonated cytidines to form a C center dot C+ base pair. Fundamental studies that aim to understand how the lengths of loops connecting the protonated C center dot C+ pairs affect intramolecular iM physical properties are described here. We characterized both the thermal stability and the pK(a) of intramolecular iMs with differing loop lengths, in both dilute solutions and solutions containing molecular crowding agents. Our results showed that intramolecular iMs with longer central loops form at pHs and temperatures higher than those of iMs with longer outer loops. Our studies also showed that increases in thermal stability of iMs when molecular crowding agents are present are dependent on the loop that is lengthened. However, the increase in pK(a) for iMs when molecular crowding agents are present is insensitive to loop length. Importantly, we also determined the proton activity of solutions containing high concentrations of molecular crowding agents to ascertain whether the increase in pK(a) of an iM is caused by alteration of this activity in buffered solutions. We determined that crowding agents alone increase the apparent pK(a) of a number of small molecules as well as iMs but that increases to iM pK(a) were greater than that expected from a shift in proton activity.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available