Quantitative transcription factor binding kinetics at the single-molecule level.

ABSTRACT: We investigated the binding interaction between the bacteriophage lambda-repressor CI and its target DNA using total internal reflection fluorescence microscopy. Large stepwise changes in the intensity of the red fluorescent protein fused to CI were observed as it associated with and dissociated from individually labeled single-molecule DNA targets. The stochastic association and dissociation were characterized by Poisson statistics. Dark and bright intervals were measured for thousands of individual events. The exponential distribution of the intervals allowed direct determination of the association and dissociation rate constants (k(a) and k(d), respectively). We resolved in detail how k(a) and k(d) varied as a function of three control parameters: the DNA length L, the CI dimer concentr

SUBMITTER: Wang Y 

PROVIDER: S-EPMC2716481 | biostudies-literature | 2009 Jan

REPOSITORIES: biostudies-literature