title: Differential depolymerization mechanisms of pectate lyases secreted by Erwinia chrysanthemi EC16.
abstract: The four pectate lyases (EC 4.2.2.2) secreted by Erwinia chrysanthemi EC16 have been individually produced as recombinant enzymes in Escherichia coli. Oligogalacturonates formed from polygalacturonic acid during reactions catalyzed by each enzyme have been determined by high-performance liquid chromatography analysis. PLa catalyzes the formation of a series of oligomers ranging from dimer to dodecamer through a random endolytic depolarization mechanism. PLb and PLc are trimer- and tetramer-generating enzymes with an identical combination of endolytic and exolytic mechanisms. PLe catalyzes a nonrandom endolytic depolymerization with the formation of dimer as the predominant product. The pectate lyases secreted by E. chrysanthemi EC16 represent a battery of enzymes with three distinct approaches to the depolymerization of plant cell walls.
authors.affiliation: Department of Microbiology and Cell Science, University of Florida, Gainesville 32611-0116.
authors.forename: J F
authors.initials: JF
authors.lastname: Preston
authors.forename: J D
authors.initials: JD
authors.lastname: Rice
authors.forename: L O
authors.initials: LO
authors.lastname: Ingram
authors.forename: N T
authors.initials: NT
authors.lastname: Keen
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D016974:Dickeya chrysanthemi / Q000201:enzymology*; D007700:Kinetics; D011133:Polysaccharide-Lyases / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D011133:Polysaccharide-Lyases; C023911:pectate lyase