Figure 2. Size Exclusion Chromatography Experiments.

Chromatographic profiles of the untagged RECQ1 (solid lane) and His₆-RECQ1 (dashed line) eluting from the Superdex200 HR 10/30 gel filtration column. The protein species were detected by protein fluorescence (λ_excitation = 290 nm and λ_emission = 340 nm). Approximately 40 μg of recombinant RECQ1 were loaded at a final concentration of 1 μM. The protein eluted in two main peaks. The first peak corresponds to a calculated molecular mass of approximately 400 kDa, whereas the second corresponds to a calculated molecular weight of approximately 155 kDa. The absence of protein eluting with the void volume highlights the lack of nonspecific aggregates. (A) RECQ1 alone. (B) RECQ1 + ssDNA (oligo(dT)₄₀). (C) RECQ1 + ATPγS. (D) RECQ1 + ssDNA (oligo(dT)₄₀) + ATPγS. Analogous results were obtained using oligo(dT)₃₀ (unpublished data).