title: Characterization of SCO4439, a D-alanyl-D-alanine carboxypeptidase involved in spore cell wall maturation, resistance, and germination in Streptomyces coelicolor.
abstract: This work contributes to the understanding of cell wall modifications during sporulation and germination in Streptomyces by assessing the biological function and biochemical properties of SCO4439, a D-alanyl-D-alanine carboxypeptidase (DD-CPase) constitutively expressed during development. SCO4439 harbors a DD-CPase domain and a putative transcriptional regulator domain, separated by a putative transmembrane region. The recombinant protein shows that DD-CPase activity is inhibited by penicillin G. The spores of the SCO4439::Tn5062 mutant are affected in their resistance to heat and acid and showed a dramatic increase in swelling during germination. The mycelium of the SCO4439::Tn5062 mutant is more sensitive to glycopeptide antibiotics (vancomycin and teicoplanin). The DD-CPase domain and the hydrophobic transmembrane region are highly conserved in Streptomyces, and both are essential for complementing the wild type phenotypes in the mutant. A model for the biological mechanism behind the observed phenotypes is proposed, in which SCO4439 DD-CPase releases D-Ala from peptidoglycan (PG) precursors, thereby reducing the substrate pool for PG crosslinking (transpeptidation). PG crosslinking regulates spore physical resistance and germination, and modulates mycelium resistance to glycopeptides. This study is the first demonstration of the role of a DD-CPase in the maturation of the spore cell wall.
authors: Área de Microbiología, Departamento de Biología Funcional and IUOPA, Facultad de Medicina, Universidad de Oviedo, 33006 Oviedo, Spain.
authors: Beatriz
authors: B
authors: Rioseras
authors: Área de Microbiología, Departamento de Biología Funcional and IUOPA, Facultad de Medicina, Universidad de Oviedo, 33006 Oviedo, Spain.
authors: Paula
authors: P
authors: Yagüe
authors: Área de Microbiología, Departamento de Biología Funcional and IUOPA, Facultad de Medicina, Universidad de Oviedo, 33006 Oviedo, Spain.
authors: María Teresa
authors: MT
authors: López-García
authors: Área de Microbiología, Departamento de Biología Funcional and IUOPA, Facultad de Medicina, Universidad de Oviedo, 33006 Oviedo, Spain.
authors: Nathaly
authors: N
authors: Gonzalez-Quiñonez
authors: Department of Biotechnology and Life Sciences, University of Insubria, via J. H. Dunant 3, 21100 Varese, Italy.|"The Protein Factory" Research Center, Politecnico of Milano, ICRM CNR Milano and University of Insubria, 21100 Varese, Italy.
authors: Elisa
authors: E
authors: Binda
authors: Department of Biotechnology and Life Sciences, University of Insubria, via J. H. Dunant 3, 21100 Varese, Italy.|"The Protein Factory" Research Center, Politecnico of Milano, ICRM CNR Milano and University of Insubria, 21100 Varese, Italy.
authors: Flavia
authors: F
authors: Marinelli
authors: Área de Microbiología, Departamento de Biología Funcional and IUOPA, Facultad de Medicina, Universidad de Oviedo, 33006 Oviedo, Spain.
authors: Angel
authors: A
authors: Manteca
mesh_terms: D002473:Cell Wall / Q000378:metabolism*; D017124:Conserved Sequence; D055786:Gene Knockout Techniques; D010400:Penicillin G / Q000378:metabolism; D011480:Protease Inhibitors / Q000378:metabolism; D000072417:Protein Domains; D046929:Serine-Type D-Ala-D-Ala Carboxypeptidase / Q000235:genetics* / Q000378:metabolism*; D013171:Spores, Bacterial / Q000201:enzymology / Q000378:metabolism; D048372:Streptomyces coelicolor / Q000201:enzymology* / Q000378:metabolism*
chemical_list: D011480:Protease Inhibitors; D046929:Serine-Type D-Ala-D-Ala Carboxypeptidase; D010400:Penicillin G