Helixconstraints and amino acid substitution in GLP-1 increase cAMP and insulin secretion but not beta-arrestin 2 signaling.
Glucagon-like peptide (GLP-1) is an endogenous hormone that induces insulin secretion from pancreatic islets and modified forms are used to treat diabetes mellitus type 2. Understanding how GLP-1 interacts with its receptor (GLP-1R) can potentially lead to more effective drugs. Modeling and NMR studies of the N-terminus of GLP-1 suggest a β-turn between residues Glu9-Phe12 and a kinked alpha helix between Val16-Gly37. N-terminal turn constraints attenuated binding affinity and activity (compounds 1-8). Lys-Asp (i, i+4) crosslinks in the middle and at the C-terminus increased alpha helicity and cAMP stimulation without much effect on binding affinity or beta-arrestin 2 recruitment (compounds 9-18). Strategic positioning of helix-inducing constraints and amino acid substitutions (Tyr16, Ala22) increased peptide helicity and produced ten-fold higher cAMP potency (compounds 19-28) over GLP-1(7-37)-NH2. The most potent cAMP activator (compound 23) was also the most potent inducer of insulin secretion.
Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia.
Fabien
F
Plisson
Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia. Electronic address: t.hill@imb.uq.edu.au.
Timothy A
TA
Hill
Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia.
Justin M
JM
Mitchell
Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia.
Huy N
HN
Hoang
Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia.
Aline D
AD
de Araujo
Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia.
Weijun
W
Xu
Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia.
Adam
A
Cotterell
Worldwide Medicinal Chemistry, Cardiovascular, Metabolic & Endocrine Diseases Research Unit, Pfizer Inc., Cambridge, MA 02140, United States.
David J
DJ
Edmonds
Worldwide Medicinal Chemistry, Cardiovascular, Metabolic & Endocrine Diseases Research Unit, Pfizer Inc., Cambridge, MA 02140, United States.
Robert V
RV
Stanton
Pharmacokinetics, Dynamics and Metabolism, Pfizer Inc., Groton, CT 06340, United States.
David R
DR
Derksen
Pharmacokinetics, Dynamics and Metabolism, Pfizer Inc., Groton, CT 06340, United States.
Paula M
PM
Loria
Worldwide Medicinal Chemistry, Cardiovascular, Metabolic & Endocrine Diseases Research Unit, Pfizer Inc., Cambridge, MA 02140, United States.
David A
DA
Griffith
Worldwide Medicinal Chemistry, Cardiovascular, Metabolic & Endocrine Diseases Research Unit, Pfizer Inc., Cambridge, MA 02140, United States.
David A
DA
Price
Worldwide Medicinal Chemistry, Cardiovascular, Metabolic & Endocrine Diseases Research Unit, Pfizer Inc., Cambridge, MA 02140, United States.
Spiros
S
Liras
Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD 4072, Australia. Electronic address: d.fairlie@imb.uq.edu.au.
David P
DP
Fairlie
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000242:Cyclic AMP / Q000378:metabolism*; D052216:Glucagon-Like Peptide 1 / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D000067757:Glucagon-Like Peptide-1 Receptor / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007769:Lactams / Q000378:metabolism; D056004:Molecular Dynamics Simulation; D009154:Mutation; D000072756:Protein Conformation, alpha-Helical; D015398:Signal Transduction; D000071560:beta-Arrestin 2 / Q000378:metabolism*
D000067757:Glucagon-Like Peptide-1 Receptor; D007328:Insulin; D007769:Lactams; D000071560:beta-Arrestin 2; D052216:Glucagon-Like Peptide 1; D000242:Cyclic AMP
Beta arrestin-2; Diabetes; GLP-1; Insulin-release; α-helix