title: Biochemical characterization of the SPATE members EspPα and EspI.
abstract: The activity of serine proteases is influenced by their substrate specificity as well as by the physicochemical conditions. Here, we present the characterization of key biochemical features of the two SPATE members EspPα and EspI from Shiga-toxin producing Escherichia coli (STEC) and enterohemorrhagic E. coli (EHEC). Both proteases show high activity at conditions mimicking the human blood stream. Optimal activities were observed at slightly alkaline pH and low millimolar concentrations of the divalent cations Ca2+ and Mg2+ at physiological temperatures indicating a function in the human host. Furthermore, we provide the first cleavage profile for EspI demonstrating pronounced specificity of this protease.
authors.affiliation: Institute of Food Chemistry, Corrensstraße 45, 48149 Münster, Germany.
authors.forename: André
authors.initials: A
authors.lastname: Weiss
authors.affiliation: Institute of Food Chemistry, Corrensstraße 45, 48149 Münster, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Kortemeier
authors.affiliation: Institute of Food Chemistry, Corrensstraße 45, 48149 Münster, Germany. jbrockm@uni-muenster.de.
authors.forename: Jens
authors.initials: J
authors.lastname: Brockmeyer
mesh_terms: D002118:Calcium / Q000494:pharmacology; D002863:Chromogenic Compounds / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000302:isolation & purification / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000494:pharmacology; D009842:Oligopeptides / Q000378:metabolism*; D059748:Proteolysis; D012697:Serine Endopeptidases / Q000302:isolation & purification / Q000378:metabolism*; D013379:Substrate Specificity; D013696:Temperature; D037521:Virulence Factors / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D002863:Chromogenic Compounds; D029968:Escherichia coli Proteins; C556113:EspI protein, E coli; D009842:Oligopeptides; D037521:Virulence Factors; C107189:EspP protein, E coli; D012697:Serine Endopeptidases; D008274:Magnesium; D002118:Calcium