FIG 1.

Schematic representation of the LEXAS library expression and analysis procedure. (Step 1) Streptomyces DNA fragments of ca. 100 kb are cloned into the mobilizable BAC vector pHL921. (Step 2) Using a triparental mating, the pHL921-derived BAC clones are transferred well to spot from E. coli DH10B to the expression host S. lividans SBT5. DNA and clones containing antibiotic biosynthetic gene clusters are highlighted in purple or blue. (Step 3) Replicas of the SBT5 clones are screened for antimicrobial activity using multiple indicator strains. (Steps 4a and b) HPLC-MS analysis of metabolites and DNA sequence analyses of active clones.