Fig. 3 NanoDrop™ spectrum for different RBP preps (protein molecular weight ¼ 43 kDa). (a) 260/280 nm
ratio ¼ 1.33. Protein concentration ¼ 6.4 mg/mL. The high 260/280 nm ratio is indicative of RNA contamination, and this apoform protein sample did not crystallize. (b) A different prep for the same protein.
260/280 nm ratio ¼ 0.59. Protein concentration ¼ 6.8 mg/mL. The 260/280 nm ratio is much lower
compared with the sample in (a), indicating that there is little or no RNA contamination. In this case, the
purified apoform protein sample crystallized. Data provided by Dr. Paul Owen (Cancer Research UK Therapeutic Discovery Laboratories, London, UK)
ratio ¼ 1.33. Protein concentration ¼ 6.4 mg/mL. The high 260/280 nm ratio is indicative of RNA contamination, and this apoform protein sample did not crystallize. (b) A different prep for the same protein.
260/280 nm ratio ¼ 0.59. Protein concentration ¼ 6.8 mg/mL. The 260/280 nm ratio is much lower
compared with the sample in (a), indicating that there is little or no RNA contamination. In this case, the
purified apoform protein sample crystallized. Data provided by Dr. Paul Owen (Cancer Research UK Therapeutic Discovery Laboratories, London, UK)