Introduction of a mini-gene encoding a five-amino acid peptide confers erythromycin resistance on Bacillus subtilis and provides temporary erythromycin protection in Proteus mirabilis

A 15-bp mini-gene was introduced into Bacillus subtilis and into stable pro toplast-like L-forms of Proteus mirabilis. This mini-gene encoded the pepti de MVLFV and modeled a fragment of Escherichia coli 23S rRNA responsible fo r E. coli erythromycin (Ery) resistance. Expression of the introduced mini- gene conferred permanent fry resistance on B. subtilis. In L-forms of P. mi rabilis, the fry-protective effect was maintained in the course of several generations. Herewith, the mechanism of Fry resistance mediated by expressi on of specific short peptides was shown to exist in evolutionary distant ba cteria. Three new plasmids were constructed containing the gene under study transcriptionally fused with the genes encoding glutamylendopeptidase of B acillus licheniformis or delta-endotoxin of Bacillus thuringiensis. The fry resistance pentapeptide (E-peptide) mini-gene served as an efficient direc t transcriptional reporter and allowed to select bacillar glutamylendopepti dase with improved productivity. The mini-genes encoding E-peptides may be applied as selective markers to transform both Gram-positive and Gram-negat ive bacteria. The small size of the E-peptide mini-genes makes them attract ive selective markers for vector construction. (C) 2000 Federation of Europ ean Microbiological Societies. Published by Elsevier Science B.V. All right s reserved.