SMALL MOBILIZABLE MULTIPURPOSE CLONING VECTORS DERIVED FROM THE ESCHERICHIA-COLI PLASMIDS PK18 AND PK19 - SELECTION OF DEFINED DELETIONS INTHE CHROMOSOME OF CORYNEBACTERIUM-GLUTAMICUM

Here we describe small mobilizable vectors based on the Escherichia co li plasmids pK18 and pK19. We combined the useful properties of the pK plasmids (e.g., multiple cloning site, lacZ alpha fragment, sequencin g with M13 primers) with the broad-host-range transfer machinery of pl asmid RP4 and a modified sacB gene from Bacillus subtilis. The new pK derivatives can be transferred by RP4-mediated conjugation into a wide range of Gram(-) and Gram(+) bacteria, and should facilitate gene dis ruption and allelic exchange by homologous recombination. As an applic ation example, the generation of a defined deletion of the hom-thrB ge nes in the chromosome of the Gram(+) bacterium Corynebacterium glutami cum glutamicum is presented.