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Abstract

The present invention relates to the simple, gentle, and efficient extraction of biological material from Escherichia coli (E. coli). The use of E. coli in research laboratories depends on the ability to prepare lysates to isolate the desired products under investigation. The present invention includes methods and engineered E. coli strains that are capable of rapid controlled lysis or herein 'autolysis'. The XJa strains were made from JM109 and the XJb strains from BL21 by insertion of the .lamda. R or (.lamda. SR) lytic endolysin gene to replace the tightly regulated araB gene. Thus, arabinose becomes a non-metabolizable inducer and the controlled autolysis phenotype is induced by the P.sub.BAD promoter by the presence of saturating arabinose. Upon induction of the bacteriophage .lamda.R endolysin, the E. coli remains intact but is efficiently lysed after one freeze-thaw cycle. The present invention is usable with many different buffer systems and is flexible in this regard. The controlled autolysis phenotype shows increased yields and purity of extracted protein compared to detergent based lysis or traditional sonication lysis methods. The present invention is useful for routine protein expression or nucleic acid extraction and also for high-through-put manipulation involving protein or nucleic acid from E. coli.

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First Claim