title: Conformational analysis of neuropeptide Y-[18-36] analogs in hydrophobic environments.
abstract: The interactive and conformational behavior of a series of neuropeptide Y-[18-36] (NPY-[18-36]) analogs in hydrophobic environments have been investigated using reversed-phase high-performance liquid chromatography (RP-HPLC) and circular dichroism (CD) spectroscopy. The peptides studied comprised a series of 16 analogs of NPY-[18-36], each containing a single D-amino acid substitution. The influence of these single L-->D substitutions on the alpha-helical conformation of the NPY-[18-36] analogs in different solvent environments was determined by CD spectroscopy. Retention parameters related to the hydrophobic contact area and the affinity of interaction were determined with an n-octadecyl (C18) adsorbent. Structural transitions for all peptides were manifested as significant changes in the hydrophobic binding domain and surface affinity between 4 degrees C and 37 degrees C. The results indicated that the central region of NPY-[18-36] (residues 23-33) is important for maintenance of the alpha-helical conformation. Moreover, L-->D amino acid residue substitutions within the N- and C-terminal regions, as well as Asn29 and Leu30, do not appear to affect the secondary structure of the peptide. These studies demonstrate that RP-HPLC provides a powerful adjunct for investigations into the induction of stabilized secondary structure in peptides upon their interaction with hydrophobic surfaces.
authors.affiliation: Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia.
authors.forename: E
authors.initials: E
authors.lastname: Lazoura
authors.forename: I
authors.initials: I
authors.lastname: Maidonis
authors.forename: E
authors.initials: E
authors.lastname: Bayer
authors.forename: M T
authors.initials: MT
authors.lastname: Hearn
authors.forename: M I
authors.initials: MI
authors.lastname: Aguilar
mesh_terms: D000595:Amino Acid Sequence; D000803:Angiotensin I / Q000737:chemistry; D000804:Angiotensin II / Q000737:chemistry; D000805:Angiotensin III / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D008961:Models, Structural; D008969:Molecular Sequence Data; D009478:Neuropeptide Y / Q000737:chemistry*; D010446:Peptide Fragments / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D013329:Structure-Activity Relationship; D013816:Thermodynamics
chemical_list: D009478:Neuropeptide Y; D010446:Peptide Fragments; D010455:Peptides; D000804:Angiotensin II; C059889:neuropeptide Y (18-36); D000805:Angiotensin III; D000803:Angiotensin I