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Structure and function of a hypothetical Pseudomonas aeruginosa protein PA1167 classified into family PL-7: a novel alginate lyase with a beta-sandwich fold.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2004 Jul 23; Vol. 279 (30), pp. 31863-72. Date of Electronic Publication: 2004 May 10. - Publication Year :
- 2004
-
Abstract
- Structural and functional analyses of alginate lyases are important in the clarification of the biofilm-dependent ecosystem in Pseudomonas aeruginosa and in the development of therapeutic agents for bacterial disease. Most alginate lyases are classified into polysaccharide lyase (PL) family-5 and -7 based on their primary structures. Family PL-7 enzymes are still poorly characterized especially in structural properties. Among family PL-7, a gene coding for a hypothetical protein (PA1167) homologous to Sphingomonas alginate lyase A1-II was found to be present in the P. aeruginosa genome. PA1167 overexpressed in Escherichia coli cleaved glycosidic bonds in alginate and released unsaturated saccharides, indicating that PA1167 is an alginate lyase catalyzing a beta-elimination reaction. The enzyme acted preferably on heteropolymeric regions endolytically and worked most efficiently at pH 8.5 and 40 degrees C. The specific activity of PA1167, however, was much weaker than that of the known alginate lyase AlgL, suggesting that AlgL plays a main role in alginate depolymerization in P. aeruginosa. In addition to this specific activity, differences were found between PA1167 and AlgL in enzyme properties such as molecular mass, optimum pH, salt effect, and substrate specificity. The first crystal structure of the family PL-7 alginate lyase was determined at 2.0 A resolution. PA1167 was found to form a glove-like beta-sandwich composed of 15 beta-strands and 3 alpha-helices. The structural difference between the beta-sandwich PA1167 of family PL-7 and alpha/alpha-barrel AlgL of family PL-5 may be responsible for the enzyme characteristics. Crystal structures of polysaccharide lyases determined so far indicate that they can be assigned to three folding groups having parallel beta-helix, alpha/alpha-barrel, and alpha/alpha-barrel + antiparallel beta-sheet structures as basic frames. PA1167 is the fourth novel folding structure found among polysaccharide lyases.
- Subjects :
- Amino Acid Sequence
Bacterial Proteins classification
Bacterial Proteins genetics
Base Sequence
Crystallography, X-Ray
DNA, Bacterial genetics
Models, Molecular
Molecular Sequence Data
Polysaccharide-Lyases classification
Polysaccharide-Lyases genetics
Protein Conformation
Pseudomonas aeruginosa genetics
Recombinant Proteins chemistry
Recombinant Proteins genetics
Recombinant Proteins metabolism
Sequence Homology, Amino Acid
Substrate Specificity
Bacterial Proteins chemistry
Bacterial Proteins metabolism
Polysaccharide-Lyases chemistry
Polysaccharide-Lyases metabolism
Pseudomonas aeruginosa enzymology
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 279
- Issue :
- 30
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 15136569
- Full Text :
- https://doi.org/10.1074/jbc.M402466200