Effects of Polyamine Binding on the Stability of DNA i-Motif Structures.

ABSTRACT: B-form DNA can adopt alternative structures under conditions such as superhelical duress. Alternative DNA structures are favored when there is asymmetric distribution of guanosine and cytosine on complimentary DNA strands. A guanosine-rich strand can form a four-stranded structure known as a quadruplex (G4). The complimentary cytosine-rich strand can utilize intercalating cytosine-cytosine base pairing to form a four-stranded structure known as the i-motif (iM). Both secondary structures are energetically uphill from double-strand DNA (dsDNA), meaning that additional factors are needed for their formation. Most iMs require slightly acidic conditions for structure stabilization. However, crowding agents such as polyethylene glycols and dextrans can shift the pK _a of the iM

SUBMITTER: Molnar MM 

PROVIDER: S-EPMC6648627 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature