A short GC-rich palindrome of human mannose receptor gene coding region displays a conformational switch.

Conformational switching in DNA is fundamental to biological processes. The structural status of a palindromic GC-rich dodecamer DNA sequence, integral part of human MRC2 coding region, and a related sequence of opposite polarity from human FDX1 gene were characterized and compared. UV-melting, circular dichroism, and gel electrophoresis experiments demonstrated the formation of intermolecular structures. Although stability and molecularity of both the oligomeric structures were found to be almost identical, their secondary structures differed remarkably as A1 MRC2 sequence showed A-like and B-like DNA conformation, whereas the A2 FDX1 sequence exhibited only the A-like signatures. The study is relevant for understanding structural polymorphism at genomic locations depending on DNA sequence and solution environment.