title: Impaired Chaperone Activity of Human Heat Shock Protein Hsp27 Site-Specifically Modified with Argpyrimidine.
abstract: Non-enzymatic posttranslational modifications (nPTMs) affect at least ∼30 % of human proteins, but our understanding of their impact on protein structure and function is limited. Studies of nPTMs are difficult because many modifications are not included in common chemical libraries or protein expression systems and should be introduced site-specifically. Herein, we probed the effect of the nPTM argpyrimidine on the structure and function of human protein Hsp27, which acquires argpyrimidine at residue 188 in vivo. We developed a synthetic approach to an argpyrimidine building block, which we then incorporated at position 188 of Hsp27 through protein semisynthesis. This modification did not affect the protein secondary structure, but perturbed the oligomeric assembly and impaired chaperone activity. Our work demonstrates that protein function can be altered by a single nPTM and opens up a new area of investigation only accessible by methods that allow site-selective protein modification.
authors.affiliation: University of Vienna, Faculty of Chemistry, Institute of Biological Chemistry, Währinger Str. 38, 1090, Vienna, Austria.
authors.forename: Maria
authors.identifier: 0000-0002-3797-7355
authors.initials: M
authors.lastname: Matveenko
authors.affiliation: University of Genoa, Department of Pharmacy, Viale Benedetto XV n.3, 16132, Genoa, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Cichero
authors.affiliation: University of Genoa, Department of Pharmacy, Viale Benedetto XV n.3, 16132, Genoa, Italy.
authors.forename: Paola
authors.identifier: 0000-0001-9386-0445
authors.initials: P
authors.lastname: Fossa
authors.affiliation: University of Vienna, Faculty of Chemistry, Institute of Biological Chemistry, Währinger Str. 38, 1090, Vienna, Austria. christian.becker@univie.ac.at.
authors.forename: Christian F W
authors.identifier: 0000-0002-8890-7082
authors.initials: CF
authors.lastname: Becker
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D055551:HSP27 Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism; D006360:Heat-Shock Proteins; D006801:Humans; D018832:Molecular Chaperones; D009952:Ornithine / Q000031:analogs & derivatives* / Q000737:chemistry; D011499:Protein Processing, Post-Translational; D017433:Protein Structure, Secondary; D011743:Pyrimidines / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D013056:Spectrophotometry, Ultraviolet
chemical_list: D055551:HSP27 Heat-Shock Proteins; C057725:HSPB1 protein, human; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D011743:Pyrimidines; C107313:argpyrimidine; D009952:Ornithine
keywords: argpyrimidine; biological activity; chaperone proteins; protein modifications; protein semisynthesis