title: Identification of a chitin-binding protein secreted by Pseudomonas aeruginosa.
abstract: One of the major proteins secreted by Pseudomonas aeruginosa is a 43-kDa protein, which is cleaved by elastase into smaller fragments, including a 30-kDa and a 23-kDa fragment. The N-terminal 23-kDa fragment was previously suggested as corresponding to a staphylolytic protease and was designated LasD (S. Park and D. R. Galloway, Mol. Microbiol. 16:263-270, 1995). However, the sequence of the gene encoding this 43-kDa protein revealed that the N-terminal half of the protein is homologous to the chitin-binding proteins CHB1 of Streptomyces olivaceoviridis and CBP21 of Serratia marcescens and to the cellulose-binding protein p40 of Streptomyces halstedii. Furthermore, a short C-terminal fragment shows homology to a part of chitinase A of Vibrio harveyi. The full-length 43-kDa protein could bind chitin and was thereby protected against the proteolytic activity of elastase, whereas the degradation products did not bind chitin. The purified 43-kDa chitin-binding protein had no staphylolytic activity, and comparison of the enzymatic activities in the extracellular medium of a wild-type strain and a chitin-binding protein-deficient mutant indicated that the 43-kDa protein supports neither chitinolytic nor staphylolytic activity. We conclude that the 43-kDa protein, which was found to be produced by many clinical isolates of P. aeruginosa, is a chitin-binding protein, and we propose to name it CbpD (chitin-binding protein D).
authors.affiliation: Department of Molecular Microbiology and Institute of Biomembranes, Utrecht University, 3584 CH Utrecht, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Folders
authors.forename: J
authors.initials: J
authors.lastname: Tommassen
authors.forename: L C
authors.initials: LC
authors.lastname: van Loon
authors.forename: W
authors.initials: W
authors.lastname: Bitter
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D001665:Binding Sites; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism; D002686:Chitin / Q000378:metabolism*; D006868:Hydrolysis; D008969:Molecular Sequence Data; D011485:Protein Binding; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000235:genetics / Q000494:pharmacology; D013210:Staphylococcus / Q000187:drug effects
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; C404568:chitin-binding protein D, Pseudomonas aeruginosa; D002686:Chitin; D002482:Cellulose; C095769:LasD protein, Pseudomonas aeruginosa; D012697:Serine Endopeptidases