title: Design, conformational studies and analysis of structure-function relationships of PTH (1-11) analogues: the essential role of Val in position 2.
abstract: The N-terminal 1-34 segment of parathyroid hormone (PTH) is fully active in vitro and in vivo and it elicits all the biological responses characteristic of the native intact PTH. Recent studies reported potent helical analogues of the PTH (1-11) with helicity-enhancing substitutions. This work describes the synthesis, biological activity, and conformational studies of analogues obtained from the most active non-natural PTH (1-11) peptide H-Aib-Val-Aib-Glu-Ile-Gln-Leu-Nle-His-Gln-Har-NH2; specifically, the replacement of Val in position 2 with D-Val, L-(αMe)-Val and N-isopropyl-Gly was studied. The synthesized analogues were characterized functionally by in-cell assays and their structures were determined by CD and NMR spectroscopy. To clarify the relationship between the structure and activity, the structural data were used to generate a pharmacophoric model, obtained overlapping all the analogues. This model underlines the fundamental functional role of the side chain of Val2 and, at the same time, reveals that the introduction of conformationally constrained Cα-tetrasubstituted α-amino acids in the peptides increases their helical content, but does not necessarily ensure significant biological activity.
authors.affiliation: Department of Molecular Sciences and Nanosystems, Università Ca' Foscari di Venezia, Dorsoduro, 2137, 30123, Venice, Italy. caporaleandrea74@gmail.com
authors.forename: A
authors.initials: A
authors.lastname: Caporale
authors.forename: L
authors.initials: L
authors.lastname: Gesiot
authors.forename: M
authors.initials: M
authors.lastname: Sturlese
authors.forename: A
authors.initials: A
authors.lastname: Wittelsberger
authors.forename: S
authors.initials: S
authors.lastname: Mammi
authors.forename: E
authors.initials: E
authors.lastname: Peggion
mesh_terms: D000595:Amino Acid Sequence; D002460:Cell Line; D057809:HEK293 Cells; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010281:Parathyroid Hormone / Q000737:chemistry* / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D044168:Receptor, Parathyroid Hormone, Type 1 / Q000378:metabolism; D013329:Structure-Activity Relationship; D014633:Valine / Q000737:chemistry*
chemical_list: D010281:Parathyroid Hormone; D010446:Peptide Fragments; D044168:Receptor, Parathyroid Hormone, Type 1; C454802:parathyroid hormone (1-11); D014633:Valine