title: Discovery and structural characterization of a phospholamban-binding cyclic peptide and design of novel inhibitors of phospholamban.
abstract: The interplay between cardiac sarcoplasmic Ca(2+)ATPase and phospholamban is a key regulating factor of contraction and relaxation in the cardiac muscle. In heart failure, aberrations in the inhibition of sarcoplasmic Ca(2+)ATPase by phospholamban are associated with anomalies in cardiac functions. In experimental heart failure models, modulation of the interaction between these two proteins has been shown to be a potential therapeutic approach. The aim of our research was to find molecules able to interfere with the inhibitory activity of phospholamban on sarcoplasmic Ca(2+)ATPase. For this purpose, a portion of phospholamban was synthesized and used as target for a phage-display peptide library screening. The cyclic peptide C-Y-W-E-L-E-W-L-P-C-A was found to bind to phospholamban (1-36) with high specificity. Its functional activity was tested in Ca(2+)uptake assays utilizing preparations from cardiac sarcoplasmic reticulum. By synthesizing and testing a series of alanine point-mutated cyclic peptides, we identified which amino acid was important for the inhibition of the phospholamban function. The structures of active and inactive alanine-mutated cyclic peptides, and of phospholamban (1-36), were determined by NMR. This structure-activity analysis allowed building a model of phospholamban -cyclic peptide complex. Thereafter, a simple pharmacophore was defined and used for the design of small molecules. Finally, examples of such molecules were synthesized and characterized as phospholamban inhibitors.
authors.affiliation: Orion Pharma, R&D, P.O. Box 65, 02101 Espoo, Finland.
authors.forename: Carola
authors.initials: C
authors.lastname: Tilgmann
authors.forename: Piero
authors.initials: P
authors.lastname: Pollesello
authors.forename: Martti
authors.initials: M
authors.lastname: Ovaska
authors.forename: Juha
authors.initials: J
authors.lastname: Kaivola
authors.forename: Jarmo
authors.initials: J
authors.lastname: Pystynen
authors.forename: Eija
authors.initials: E
authors.lastname: Tiainen
authors.forename: Marjo
authors.initials: M
authors.lastname: Yliperttula
authors.forename: Arto
authors.initials: A
authors.lastname: Annila
authors.forename: Jouko
authors.initials: J
authors.lastname: Levijoki
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000037:antagonists & inhibitors / Q000138:chemical synthesis / Q000378:metabolism*; D015195:Drug Design; D004353:Drug Evaluation, Preclinical; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects; D006801:Humans; D008958:Models, Molecular; D009206:Myocardium / Q000378:metabolism; D019151:Peptide Library; D010456:Peptides, Cyclic / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D011485:Protein Binding; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000378:metabolism; D054852:Small Molecule Libraries / Q000737:chemistry / Q000494:pharmacology; D013329:Structure-Activity Relationship; D000099211:Phospholamban
chemical_list: D002118:Calcium; D002135:Calcium-Binding Proteins; D019151:Peptide Library; D010456:Peptides, Cyclic; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D054852:Small Molecule Libraries; D000099211:Phospholamban