Structure-function analysis of a series of glucagon-like peptide-1 analogs.
We have used NMR in conjunction with measurements of functional bioactivity to define the receptor-binding structure of glucagon-like peptide-1 (GLP-1.) Identification of the important residues for binding was accomplished by the substitution of amino acids at sites that seemed likely, from an examination of the amino acid sequence and from previously published observations, to be important in the three-dimensional (3D) structure of the molecule. Identification of the receptor-bound conformation of GLP-1, because it is a flexible peptide, required constraint of the peptide backbone into a predetermined 3D structure. Constraint was achieved by the introduction of disulfide bonds and specific side chain-side chain cross-links. The biological relevance of the synthetic structure of each rigidified peptide was assessed by measurement of its ability to bind to the receptor present on RINm5F cells and to elicit a functional response, cyclic AMP production. NMR solution structures were obtained for the most biologically relevant of these analogs. The results of this study indicated that the residues necessary for the biological activity of GLP-1 occupy approximately three equally-spaced regions of the peptide 3D structure, at the corners of an equilateral triangle whose sides are, at a minimum estimate, 12-15A.
Parker
J C
JC
Pfizer Inc., Central Research Division, Groton, Connecticut 06340, USA. janice_c_parker@groton.pfizer.com
Andrews
K M
KM
Rescek
D M
DM
Massefski
W
W
Andrews
G C
GC
Contillo
L G
LG
Stevenson
R W
RW
Singleton
D H
DH
Suleske
R T
RT
D000595:Amino Acid Sequence; D002460:Cell Line; D005934:Glucagon / Q000737:chemistry* / Q000378:metabolism; D052216:Glucagon-Like Peptide 1; D004763:Glucagon-Like Peptides; D006801:Humans; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism; D010455:Peptides / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D011498:Protein Precursors / Q000737:chemistry* / Q000378:metabolism; D013329:Structure-Activity Relationship
D010446:Peptide Fragments; D010455:Peptides; D011498:Protein Precursors; D004763:Glucagon-Like Peptides; D052216:Glucagon-Like Peptide 1; D005934:Glucagon; C051322:glucagon-like peptide 1 (7-37)