TABLE 1.

Average HPV-16 L1 protein yields for the different capsomere constructsa

L1 capsomere constructL1 protein yield (mg)/liter of bacterial cultureAmt (EU/mg) of LPS/mg of L1
L1ΔN100.271,750
L1ΔN10dCys0.232,400
L1ΔN10Δ414-4310.342,900
L1ΔN10Δ408-4310.41850
L1ΔN10ΔC290.50860
L1ΔN10dCysΔC290.45780
L1ΔN10Δ414-431ΔC290.591,450
L1ΔN10Δ408-431ΔC290.75410
  • a The L1 proteins were expressed in and purified from E. coli as described previously by Chen et al. (11). Subsequently, gel filtration chromatography was performed using a Superdex 200 column. Protein amounts were determined by Bradford assay and by densitometry on a Coomassie blue-stained SDS-PAG using the ImageJ software (NIH). LPS contamination was measured using the colorimetric assay QCL-1000 (Lonza). The values in the table are the median values for at least three independent purifications.