Primary structure and conformational analysis of peptide methionine-tyrosine, a peptide related to neuropeptide Y and peptide YY isolated from lamprey intestine.
A peptide belonging to the pancreatic-polypeptide-fold family of regulatory peptides has been isolated from the intestine of an Agnathan, the sea lamprey (Petromyzon marinus). The primary structure of the peptide (termed peptide methionine-tyrosine) was established as Met-Pro-Pro-Lys-Pro-Asp-Asn- Pro-Ser-Pro10-Asp-Ala-Ser-Pro-Glu-Leu-Ser-Lys-Tyr20-Met-Leu- Ala-Val-Arg-Asn- Tyr-Ile-Asn-Leu30-Ile-Thr-Arg-Gln-Arg-Tyr CONH2. This sequence shows stronger structural similarity with pig neuropeptide Y (64%), particularly in the COOH-terminal region, than with pig peptide tyrosine--tyrosine (61%) or with pig pancreatic polypeptide (42%). Molecular modelling and dynamic simulation, based upon sequence similarity with turkey pancreatic polypeptide, indicates that the conformations of the polyproline-helix-like region (residues 1-8) and the alpha-helical region (residues 15-30) in turkey pancreatic polypeptide are conserved in peptide methionine-tyrosine, and that non-bonded interactions between these domains have preserved the overall polypeptide fold in the molecule. The substitution of the otherwise totally conserved Gly9 residue by serine in lamprey peptide methionine-tyrosine, however, results in a preferred structure in which the conformation of the beta-turn between the two helical domains (residues 9-14) is appreciably different.
Conlon
J M
JM
Regulatory Peptide Center, Creighton University School of Medicine, Omaha, NE 68178.
Bjørnholm
B
B
Jørgensen
F S
FS
Youson
J H
JH
Schwartz
T W
TW
D000595:Amino Acid Sequence; D000818:Animals; D002850:Chromatography, Gel; D005768:Gastrointestinal Hormones / Q000737:chemistry*; D007421:Intestine, Small / Q000737:chemistry*; D007798:Lampreys; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009478:Neuropeptide Y / Q000737:chemistry*; D019894:Peptide YY; D010455:Peptides / Q000737:chemistry* / Q000302:isolation & purification; D011487:Protein Conformation; D012689:Sequence Homology, Nucleic Acid
D005768:Gastrointestinal Hormones; D009478:Neuropeptide Y; D010455:Peptides; D019894:Peptide YY; C069955:peptide methionine-tyrosine