title: Skl, a novel choline-binding N-acetylmuramoyl-L-alanine amidase of Streptococcus mitis SK137 containing a CHAP domain.
abstract: The skl gene from Streptococcus mitis SK137 encodes a peptidoglycan hydrolase (Skl) that has been purified and biochemically characterized. Analysis of the degradation products obtained by digestion of pneumococcal cell walls with Skl revealed that this enzyme is an N-acetylmuramoyl-L-alanine amidase (EC 3.5.1.28), showing optimum activity at 30 degrees C and at a pH of 6.5. Skl is a unique member of the choline-binding family of proteins since it contains a cysteine, histidine-dependent amidohydrolases/peptidases (CHAP) domain. The CHAP domain of Skl showed homology to lysins of unknown especificity from a variety of streptococcal prophages. Skl represents the first characterized member of a new subfamily of CHAP-containing choline-binding proteins.
authors.affiliation: Departamento de Microbiología Molecular, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Llull
authors.forename: Rubens
authors.initials: R
authors.lastname: López
authors.forename: Ernesto
authors.initials: E
authors.lastname: García
mesh_terms: D000595:Amino Acid Sequence; D002473:Cell Wall / Q000378:metabolism; D002794:Choline / Q000378:metabolism*; D002850:Chromatography, Gel; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017422:Sequence Analysis, DNA; D034361:Streptococcus mitis / Q000201:enzymology*; D013296:Streptococcus pneumoniae / Q000378:metabolism
chemical_list: D009238:N-Acetylmuramoyl-L-alanine Amidase; D002794:Choline