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Semisynthetic D-His1,N epsilon-acetimidoglucagon: structure-function relationships
A M Mahrenholz1, K C Flanders, N M Hoosein
1Department of Chemistry, Indiana University School of Medicine, Bloomington 47405.
Archives of Biochemistry and Biophysics
|September 1, 1987
Summary
Researchers modified glucagon by replacing a key histidine residue with its D-isomer. This D-His1 glucagon analog acts as a full agonist but has a 10-fold lower binding affinity, impacting receptor interaction.
Area of Science:
- Biochemistry
- Molecular Biology
- Endocrinology
Background:
- Glucagon is a crucial hormone regulating blood glucose levels.
- Understanding glucagon-receptor interactions is vital for metabolic disease research.
Purpose of the Study:
- To investigate the role of the N-terminal histidine residue in glucagon's structure and function.
- To synthesize and characterize a D-His1 glucagon analog.
Main Methods:
- Semisynthetic strategy for analog preparation.
- Circular dichroism spectroscopy for secondary structure analysis.
- Competitive binding and adenylate cyclase activation assays using rat liver plasma membranes.
Main Results:
- The D-His1 glucagon analog exhibited similar secondary structure to native glucagon.
- The analog functioned as a full agonist, achieving maximal adenylate cyclase activation.
- A 10-fold reduction in binding affinity was observed for the D-His1 analog compared to native glucagon.
Conclusions:
- The N-terminal histidine is important for high-affinity glucagon binding.
- Conformational constraints upon receptor binding influence glucagon's interaction.
- This study provides insights into structure-activity relationships of glucagon analogs.