Structural and mechanical properties of individual human telomeric G-quadruplexes in molecularly crowded solutions.

ABSTRACT: Recent experiments provided controversial observations that either parallel or non-parallel G-quadruplex exists in molecularly crowded buffers that mimic cellular environment. Here, we used laser tweezers to mechanically unfold structures in a human telomeric DNA fragment, 5'-(TTAGGG)4TTA, along three different trajectories. After the end-to-end distance of each unfolding geometry was measured, it was compared with PDB structures to identify the best-matching G-quadruplex conformation. This method is well-suited to identify biomolecular structures in complex settings not amenable to conventional approaches, such as in a solution with mixed species or at physiologically significant concentrations. With this approach, we found that parallel G-quadruplex coexists with non-parallel species (1:

SUBMITTER: Dhakal S 

PROVIDER: S-EPMC3616730 | biostudies-literature | 2013 Apr

REPOSITORIES: biostudies-literature