Heterogeneity in single DNA conformational fluctuations

Non-exponential behaviour in bulk measurements of two-state molecular reactions can have different origins. The probability density for the time which one of two states is occupied during different observation interval times can be used to reveal system characteristics if single molecules are studied. An evaluation of new experimental data from single DNA molecules labeled with a fluorescent conformation probe proves the heterogeneity of the ensemble system. Also, the anomalicity is concluded to be low for single events. The evaluation method can be applied in other experiments where two-state reversible processes are studied for isolated systems.