Kinetic properties of Streptococcus pneumoniae hyaluronate lyase.

Publisher: IRL Press at Oxford University Press Country of Publication: England NLM ID: 9104124 Publication Model: Print Cited Medium: Print ISSN: 0959-6658 (Print) Linking ISSN: 09596658 NLM ISO Abbreviation: Glycobiology Subsets: MEDLINE

Original Publication: Oxford ; New York : IRL Press at Oxford University Press, c1990-

Polysaccharide-Lyases/*chemistry ; Polysaccharide-Lyases/*metabolism ; Streptococcus pneumoniae/*enzymology; Binding Sites ; Carbohydrate Sequence ; Humans ; Hyaluronic Acid/chemistry ; Hyaluronic Acid/metabolism ; Hydrolysis ; Kinetics ; Models, Molecular ; Molecular Sequence Data ; Mutation/genetics ; Polysaccharide-Lyases/genetics ; Protein Structure, Tertiary ; Streptococcus pneumoniae/genetics ; Umbilical Cord

Streptococcus pneumoniae hyaluronate lyase is a surface antigen of this bacterial pathogen, which causes significant mortality and morbidity in human populations worldwide. The primary function of this enzyme is the degradation of hyaluronan, a major component of the extracellular matrix of the tissues of practically all vertebrates. The enzyme uses a processive mode of action to degrade hyaluronan to a final product, an unsaturated disaccharide hyaluronan unit. This catalysis proceeds via a five-step proton acceptance and donation mechanism that includes substrate binding, catalysis, release of the disaccharide product, translocation of the remaining hyaluronan substrate, and proton exchange with microenvironment. Based on the analysis of the three-dimensional structure of the native enzyme and its complexes with hexasaccharide substrate and disaccharide product, several residues have been chosen for mutation studies. These mutated residues included the catalytic residues Asn349, His399, Tyr408, and residues responsible for substrate binding and translocation, Arg243 and Asn580. The comparison of the kinetic properties of the wild-type with the mutant enzymes allowed for the characterization of every mutant and the correlation of the kinetic properties of the enzyme with its structure. The comparison of the wild-type hyaluronate lyase with other polysaccharide-degrading enzymes, the hydrolases endonuclease and glucoamylase, shows striking similarity of K(m)s for all of these different enzymes.

AI 44078 United States AI NIAID NIH HHS

9004-61-9 (Hyaluronic Acid)
EC 4.2.2.- (Polysaccharide-Lyases)
EC 4.2.2.1 (hyaluronate lyase)

Date Created: 20010519 Date Completed: 20010726 Latest Revision: 20190513

20221213

10.1093/glycob/11.4.297

11358878