title: Effects of magnesium ions on recombinant human furin: selective activation of hydrolytic activity upon substrates derived from virus envelope glycoprotein.
abstract: Here we report a detailed analysis of magnesium (Mg²+) ion effects on furin hydrolysis of fluorescent resonance energy transfer decapeptide substrates derived from canonical R-X-K/R-R furin cleavage motifs within certain viral envelope glycoproteins and eukaryotic proproteins. Using virus-derived sequences a selective activation of furin by Mg²+) ions was observed as a result of cooperativity between furin subsites. Furin hydrolysis of the peptides Abz-SRRHKR↓FAGV-Q-EDDnp (from measles virus fusion protein F₀ and Abz-RERRRKKR↓GLFG-Q-EDDnp (from Asian avian influenza A, H5N1) was activated between 60- and 80-fold by MgCl₂. It appears that virus envelope glycoprotein mutations have been selected to increase their susceptibility to furin within cells, a location where Mg²+ is present in adequate concentrations for activation. Both the pH profile of furin and its intrinsic fluorescence were modified by Mg²+ ions, which bind to furin with a K(d) value of 1.1 mM.
authors.affiliation: Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Três de Maio 100, São Paulo 04044-020, Brazil.
authors.forename: Mario A
authors.initials: MA
authors.lastname: Izidoro
authors.forename: Diego M
authors.initials: DM
authors.lastname: Assis
authors.forename: Vitor
authors.initials: V
authors.lastname: Oliveira
authors.forename: Jorge A N
authors.initials: JA
authors.lastname: Santos
authors.forename: Maria A
authors.initials: MA
authors.lastname: Juliano
authors.forename: Iris
authors.initials: I
authors.lastname: Lindberg
authors.forename: Luiz
authors.initials: L
authors.lastname: Juliano
mesh_terms: D055162:Biocatalysis / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D031541:Fluorescence Resonance Energy Transfer; D045683:Furin / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis / Q000187:drug effects; D053124:Influenza A Virus, H5N1 Subtype / Q000737:chemistry / Q000235:genetics; D007477:Ions / Q000737:chemistry / Q000494:pharmacology; D008274:Magnesium / Q000737:chemistry / Q000494:pharmacology*; D009842:Oligopeptides / Q000737:chemistry; D043484:Proprotein Convertases / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D013379:Substrate Specificity; D014759:Viral Envelope Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D007477:Ions; D009842:Oligopeptides; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D014759:Viral Envelope Proteins; D043484:Proprotein Convertases; C058751:KEX2 protein, S cerevisiae; D045683:Furin; D008274:Magnesium