Conformational analysis of neuropeptide Y-[18-36] analogs in hydrophobic environments.
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.
Lazoura
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E
Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia.
Maidonis
I
I
Bayer
E
E
Hearn
M T
MT
Aguilar
M I
MI
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
D009478:Neuropeptide Y; D010446:Peptide Fragments; D010455:Peptides; D000804:Angiotensin II; C059889:neuropeptide Y (18-36); D000805:Angiotensin III; D000803:Angiotensin I