Topology-Dependent Dynamics of Single DNA Molecules

Abstract

of SAM. We determined their Mg 2þ -dependent fractional populations and conformational dynamics, including state lifetimes, interconversion rate coefficients and equilibration timescales. Riboswitches with terminator and antiterminator folds were found to coexist under all conditions; SAM binding induced only a gradual increase in the population of terminator states. Conformational transitions were much faster with bound SAM, which may be crucial for offswitching during the brief decision window before expression of the downstream gene.