title: Identification and characterization of a novel autolysin (Aae) with adhesive properties from Staphylococcus epidermidis.
abstract: Staphylococcus epidermidis biofilm formation on polymer surfaces is considered a major pathogenicity factor in foreign-body-associated infections. Previously, the 148 kDa autolysin AtlE from S. epidermidis, which is involved in the initial attachment of the cells to polymer surfaces and also binds to the extracellular matrix protein vitronectin, was characterized. Here, the characterization of a novel autolysin/adhesin (Aae) in S. epidermidis is described. Aae was identified as a 35 kDa surface-associated protein that has bacteriolytic activity and binds vitronectin. Its N-terminal amino acid sequence was determined and the respective gene, aae, was cloned. DNA-sequence analysis revealed that aae encodes a deduced protein of 324 amino acids with a predicted molecular mass of 35 kDa. Aae contains three repetitive sequences in its N-terminal portion. These repeats comprise features of a putative peptidoglycan binding domain (LysM domain) found in a number of enzymes involved in cell-wall metabolism and also in some adhesins. Expression of aae by Escherichia coli and subsequent analysis revealed that Aae possesses bacteriolytic activity and adhesive properties. The interaction of Aae with fibrinogen, fibronectin and vitronectin was found to be dose-dependent and saturable and to occur with high affinity, by using the real-time Biomolecular Interaction Analysis (BIA). Aae binds to the Aalpha- and Bbeta-chains of fibrinogen and to the 29 kDa N-terminal fragment of fibronectin. In conclusion, Aae is a surface-associated protein with bacteriolytic and adhesive properties representing a new member of the staphylococcal autolysin/adhesins potentially involved in colonization.
authors.affiliation: Institute of Medical Microbiology, University of Münster, Domagkstr. 10, D-48149 Münster, Germany.
authors.forename: Christine
authors.initials: C
authors.lastname: Heilmann
authors.affiliation: Mikrobielle Genetik, University of Tübingen, Auf der Morgenstelle 28, D-72076 Tübingen, Germany.
authors.forename: Günther
authors.initials: G
authors.lastname: Thumm
authors.affiliation: Division of Microbiology, GBF-National Research Center for Biotechnology, Spielmannstr. 7, D-38106 Braunschweig, Germany.
authors.forename: Gursharan S
authors.initials: GS
authors.lastname: Chhatwal
authors.affiliation: Institute of Medical Microbiology, University of Münster, Domagkstr. 10, D-48149 Münster, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Hartleib
authors.affiliation: Institute of Medical Microbiology, University of Münster, Domagkstr. 10, D-48149 Münster, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Uekötter
authors.affiliation: Institute of Medical Microbiology, University of Münster, Domagkstr. 10, D-48149 Münster, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Peters
mesh_terms: D018829:Adhesins, Bacterial / Q000032:analysis* / Q000737:chemistry / Q000502:physiology; D000595:Amino Acid Sequence; D001422:Bacterial Adhesion; D001433:Bacteriolysis; D001665:Binding Sites; D003001:Cloning, Molecular; D005340:Fibrinogen / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D008969:Molecular Sequence Data; D009238:N-Acetylmuramoyl-L-alanine Amidase / Q000032:analysis* / Q000737:chemistry / Q000502:physiology; D013212:Staphylococcus epidermidis / Q000737:chemistry* / Q000502:physiology; D019096:Vitronectin / Q000378:metabolism
chemical_list: D018829:Adhesins, Bacterial; D005353:Fibronectins; D019096:Vitronectin; D005340:Fibrinogen; D009238:N-Acetylmuramoyl-L-alanine Amidase