title: The contribution of key hydrophobic residues in ecotin to enzyme-inhibitor complex stability.
abstract: The Escherichia coli protease inhibitor ecotin is believed to be implicated in the evasion of host defenses during infection. The protein has also attracted attention as a scaffold for the design of novel, specific protease inhibitors. Ecotin interacts with its targets through two sites. Key hydrophobic residues in both sites (Leu-64, Trp-67, Tyr-69, Met-84, and Met-85) were mutated to alanine and the effects on the inhibition of trypsin, chymotrypsin, and elastase were assessed. Each of these mutant ecotin proteins tested in kinetic assays with these enzymes exerted less inhibitory potency compared to wild-type ecotin. However, these effects were relatively small and not additive.
authors.affiliation: School of Biological Sciences, Queen's University Belfast, Belfast, UK.
authors.forename: Maelíosa T C
authors.initials: MT
authors.lastname: McCrudden
authors.forename: Louise A
authors.initials: LA
authors.lastname: Ryan
authors.forename: Philip
authors.initials: P
authors.lastname: Turkington
authors.forename: David J
authors.initials: DJ
authors.lastname: Timson
mesh_terms: D000409:Alanine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics / Q000502:physiology; D001665:Binding Sites; D002918:Chymotrypsin / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D004795:Enzyme Stability; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D008969:Molecular Sequence Data; D009154:Mutation; D010196:Pancreatic Elastase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D033903:Periplasmic Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000235:genetics / Q000378:metabolism*; D014361:Trypsin Inhibitors / Q000235:genetics / Q000378:metabolism
chemical_list: C039076:Eco protein, E coli; D029968:Escherichia coli Proteins; D033903:Periplasmic Proteins; D015842:Serine Proteinase Inhibitors; D014361:Trypsin Inhibitors; D002918:Chymotrypsin; D010196:Pancreatic Elastase; D000409:Alanine