Primary structures of PYY, [Pro(34)]PYY, and PYY-(3-36) confer different conformations and receptor selectivity.
We synthesized PYY-(1-36) (nonselective between Y(1) and Y(2) receptor subtype agonists), [Pro(34)]PYY (selective for Y(1)), and PYY-(3-36) (selective for Y(2)) to determine whether solution conformation plays a role in receptor subtype selectivity. The three peptides exhibited the expected specificities in displacing labeled PYY-(1-36) from cells transfected with Y(1) receptors (dissociation constants = 0.42, 0.21, and 1,050 nM, respectively) and from cells transfected with Y(2) receptors (dissociation constants = 0.03, 710, and 0.11 nM, respectively) for PYY-(1-36), [Pro(34)]PYY, and PYY-(3-36). Sedimentation equilibrium analyses revealed that the three PYY analogs were 80-90% monomer at the concentrations used for the subsequent circular dichroism (CD) and (1)H-nuclear magnetic resonance (NMR) studies. CD analysis measured helicities for PYY-(1-36), [Pro(34)]PYY, and PYY-(3-36) of 42%, 31%, and 24%, suggesting distinct differences in secondary structure. The backbone (1)H-NMR resonances of the three peptides further substantiated marked conformational differences. These patterns support the hypothesis that Y(1) and Y(2) receptor subtype binding affinities depend on the secondary and tertiary solution state structures of PYY and its analogs.
Keire
D A
DA
The Beckman Research Institute of the City of Hope, Duarte, California 91010-0269, USA.
Mannon
P
P
Kobayashi
M
M
Walsh
J H
JH
Solomon
T E
TE
Reeve
J R
JR
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002942:Circular Dichroism; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments; D019894:Peptide YY / Q000737:chemistry*; D011487:Protein Conformation; D017476:Receptors, Neuropeptide Y / Q000737:chemistry*; D013552:Swine; D014461:Ultracentrifugation
D010446:Peptide Fragments; D017476:Receptors, Neuropeptide Y; C097212:neuropeptide Y-Y1 receptor; C095889:neuropeptide Y2 receptor; C091928:peptide YY, Pro(34)-; D019894:Peptide YY; C061785:peptide YY (3-36)