Direct chemical extraction of a recombinant viral coat protein from Escherichia coli at high cell density

The release of protein and DNA from nonrecombinant E. coli JM101 and recomb inant E. coli HMS174(DE3) expressing L1 (the major viral coat protein of hu man papillomavirus type 16) as an inclusion body was demonstrated at high c ell density (OD600 = 160). For the nonrecombinant strain, extraction effici ency decreased significantly as cell mass increased, with a high viscosity increase in the postextraction broth. A different dependence on cell concen tration was observed for the recombinant strain, with total protein extract ion efficiency exceeding 85% for both uninduced and induced cells. Almost c omplete release of the recombinant L1 protein was achieved at high cell con centration (OD600 = 80 similar to 160) without the use of reducing agent. T his greatly extends the concentration range for chemical extraction. (C) 20 01 John Wiley & Sons, Inc.