E. COLI MUTANT STRAIN SHOWING DECREASED NUCLEIC ACID DEGRADATION AND INCREASED PROTEIN SYNTHESIS

摘要

PURPOSE: E. coli A106 (KFCC-11066) having weak nucleic acid degradation and strong protein synthesis is provided which can be used as an expression host for the production of recombinant proteins. CONSTITUTION: Wild type of E. coli W3110, NM522 and pop2136 are cultivated in LB medium and cells are harvested by centrifugation. NTG is treated and cells are spread on minimal medium plate containing GMP or XMP. Slow growing colonie are selected. The nucleic acid degradation activity of mutants are compared with that of wild type. Three mutants show that the nucleic acid degradation activities are decreased by 70-85% based on the wild type. XMP aminase and trehalose synthetase are expressed highly in the mutant cell. XMP aminase expressed in the mutant is used to produce GMP from XMP and trehalose synthetase is used to produce trehalose from maltose.