The enigmatic lack of glucose utilization in Streptomyces clavuligerus is due to inefficient expression of the glucose permease gene

Abstract

Streptomyces clavuligerusATCC 27064 is unable to use glucose but has genes for a glucose permease (glcP) and a glucose kinase (glkA). Transformation ofS. clavuligerus27064 with theStreptomyces coelicolor glcP1gene with its own promoter results in a strain able to grow on glucose. TheglcPgene ofS. clavuligerusencodes a 475 amino acid glucose permease with 12 transmembrane segments. GlcP is a functional protein when expressed from theS. coelicolor glcP1promoter and complements two different glucose transport-negativeEscherichia colimutants. Transcription studies indicate that theglcPpromoter is very weak and does not allow growth on glucose. These results suggest thatS. clavuligerusinitially contained a functional glucose permease gene, like most otherStreptomycesspecies, and lost the expression of this gene by adaptation to glucose-poor habitats.