Multiplicity in the Genes of Carbon Metabolism in Antibiotic-Producing Streptomycetes

Abstract

Streptomycetes exhibit genetic multiplicity, like many other microorganisms, and redundancy occurs in many of the genes involved in carbon metabolism. The enzymes of the glycolytic pathway presenting the greatest multiplicity were phosphofructokinase, fructose 1,6-bisphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase, and pyruvate kinase. The genes that encode citrate synthase and subunits of the succinate dehydrogenase complex are the ones that show the greatest multiplicity, while in the phosphoenolpyruvate-pyruvate-oxaloacetate node, only malic enzymes and pyruvate phosphate dikinase present two copies in some Streptomyces. The extra DNA from these multiple gene copies can be more than 50 kb, and the question arises whether all of these genes are transcribed and translated. As far as we know, there is few information about the transcription of these genes in any of this Streptomyces, nor if any of the activities that are encoded by a single gene could be limiting both for growth and for the formation of precursors of the antibiotics produced by these microorganisms. Therefore, it is important to study the transcription and translation of genes involved in carbon metabolism in antibiotic-producing Streptomyces growing on various sugars.