title: Rapid Discovery of Potent and Selective Glycosidase-Inhibiting De Novo Peptides.
abstract: Human pancreatic α-amylase (HPA) is responsible for degrading starch to malto-oligosaccharides, thence to glucose, and is therefore an attractive therapeutic target for the treatment of diabetes and obesity. Here we report the discovery of a unique lariat nonapeptide, by means of the RaPID (Random non-standard Peptides Integrated Discovery) system, composed of five amino acids in a head-to-side-chain thioether macrocycle and a further four amino acids in a 310helical C terminus. This is a potent inhibitor of HPA (Ki= 7 nM) yet exhibits selectivity for the target over other glycosidases tested. Structural studies show that this nonapeptide forms a compact tertiary structure, and illustrate that a general inhibitory motif involving two phenolic groups is often accessed for tight binding of inhibitors to HPA. Furthermore, the work reported here demonstrates the potential of this methodology for the discovery of de novo peptide inhibitors against other glycosidases.
authors.affiliation: Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-0033 Tokyo, Japan.
authors.forename: Seino A K
authors.initials: SAK
authors.lastname: Jongkees
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
authors.forename: Sami
authors.initials: S
authors.lastname: Caner
authors.affiliation: Centre for High-Throughput Biology, Michael Smith Laboratories, 185 East Mall, Vancouver, BC V6T 1Z4, Canada; Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada.
authors.forename: Christina
authors.initials: C
authors.lastname: Tysoe
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
authors.forename: Gary D
authors.initials: GD
authors.lastname: Brayer
authors.affiliation: Centre for High-Throughput Biology, Michael Smith Laboratories, 185 East Mall, Vancouver, BC V6T 1Z4, Canada; Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada; Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Withers
authors.affiliation: Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-0033 Tokyo, Japan. Electronic address: hsuga@chem.s.u-tokyo.ac.jp.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Suga
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D020128:Inhibitory Concentration 50; D007700:Kinetics; D008968:Molecular Conformation; D056004:Molecular Dynamics Simulation; D055292:Pancreatic alpha-Amylases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D019151:Peptide Library; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D012343:RNA, Transfer / Q000737:chemistry / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D019151:Peptide Library; D010455:Peptides; D012343:RNA, Transfer; D055292:Pancreatic alpha-Amylases
keywords: RaPID system; amylases; carbohydrate-active enzymes; diabetes; genetic code reprogramming; in vitro selection; macrocyclic peptides; peptide inhibitors