Streptomyces genetics: a genomic perspective.

Streptomycetes are gram-positive, soil-inhabiting bacteria of the order Actinomycetales. These organisms exhibit an unusual, developmentally complex life cycle and produce many economically important secondary metabolites, such as antibiotics, immunosuppressants, insecticides, and anti-tumor agents. Streptomyces species have been the subject of genetic investigation for over 50 years, with many studies focusing on the developmental cycle and the production of secondary metabolites.

The loading domain of the erythromycin polyketide synthase is not essential for erythromycin biosynthesis in Saccharopolyspora erythraea.

6-Deoxyerythronolide B synthase (DEBS) is a large multifunctional enzyme that catalyses the biosynthesis of the erythromycin polyketide aglycone. DEBS is organized into six modules, each containing the enzymic domains required for a single condensation of carboxylic acid residues which make up the growing polyketide chain. Module 1 is preceded by loading acyltransferase (AT-L) and acyl carrier protein (ACP-L) domains, hypothesized to initiate polyketide chain growth with a propionate-derived moiety.

Gene disruption and replacement in the rapamycin-producing Streptomyces hygroscopicus strain ATCC 29253.

A system for gene disruption and replacement based on a streptomycete temperate phage vector was developed to introduce DNA in the rapamycin-producing Streptomyces hygroscopicus strain ATCC 29253. This will be useful in attempts to produce, through genetic manipulation, novel forms of the therapeutically important immunosuppressive drug rapamycin. Recombinant phages were constructed from the phi C31 phage derivative KC515 (C+ attp) carrying a thiostrepton or viomycin resistance gene along with segments of the S.