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. Author manuscript; available in PMC: 2016 Sep 25.
Published in final edited form as: J Mol Biol. 2015 Jul 26;427(19):3123–3136. doi: 10.1016/j.jmb.2015.07.015

Fig. 3. DNA segments in solution accelerate dissociation of Fis from a 10 kb DNA.

Fig. 3

Following binding of 20 nM Fis and washing out of the Fis solution, DNA segments in buffer were introduced, leading to a return of DNA extension to its naked DNA length. Time courses for extension at (A) 2 ng/μl, (B) 20 ng/μl and (C) 100 ng/μl herring sperm DNA (HS-DNA) are shown; in addition we carried out experiments using 5, 10 and 50 ng/μl DNA. Protein-free buffer washes were administered before the addition of competitor DNA so that no excess protein was present in the flow cell. (D) Off rate koff inferred from rates of relaxation of DNA length as a function of HS-DNA concentration. When no competitor DNA was added, the rate was undetectably small, but increased as DNA concentration was increased, up to roughly 20 ng/μl. However, once the DNA concentration exceeded 20 ng/μl the rate of release of protein leveled off.