Glycosylation of a Streptomyces coelicolor A3(2) cell envelope protein is required for infection by bacteriophage φC31

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Abstract
Mutants of Streptomyces coelicolor A3(2) J1929 (ΔpglY) were isolated that were resistant to the Streptomyces temperate phage φC31. These strains could be transfected with φC31 DNA, but could not act as infective centres after exposure to phage. Thus, it was concluded that infection was blocked at the adsorption/DNA injection step. The mutants fell into three classes. Class I mutants were complemented by a gene, SCE87.05, isolated from the cosmid library of S. coelicolor A3(2). The product of SCE87.05 had good overall homology to a Mycobacterium tuberculosis hypothetical protein and regions with similarity to dolichol phosphate-d-mannose:protein O-d-mannosyltransferases. Concanavalin A (ConA) inhibited φC31 infection of S. coelicolor J1929, and this could be partially reversed by the addition of the sugar, α-d-methyl-pyranoside. Moreover, glycosylated proteins from J1929, but not from the class I mutant DT1017, were detected using ConA as a probe in Western blots. Class I and II mutants were sensitive to φC31hc, a previously isolated phage exhibiting an extended host range phenotype, conferred by h. A phage with the same phenotype, φDT4002, was isolated independently, and a missense mutation was found in a putative tail gene. It is proposed that the φC31 receptor is a cell wall glycoprotein, and that the φC31h mutation compensates for the lack of glycosylation of the receptor.