CRM METHOD AND PLASMID FOR PRODUCTION OF CRM PROTEIN AND DIPHTHERIA TOXIN

摘要

The present invention relates to novel methods and plasmid systems for producing abundant amounts of CRM 197 protein diphtheria toxin and other CRM proteins associated with diphtheria toxin, as well as microorganisms transformed by said new plasmid.;Particularly preferred DNA plasmids, namely plasmid pNG2-22 and the name pPX 3511 combining the genes for CRM197 from non-toxin source beta phage, are described. The new plasmid system can transform strains of Corynebacterium diphtheriae into strains capable of expressing high levels of CRM 197 protein without the use of multiple lysogens. The present invention provides a precise means for increasing protein production without the need to manipulate expression vectors, for example by increasing promoter strength or removing promoters by iron regulation.