Related Experiment Videos
Distinguishing among protein kinases by substrate specificities
N E Thomas1, H N Bramson, A C Nairn
1Laboratory of Bioorganic Chemistry and Biochemistry, Rockefeller University, New York, New York 10021.
Biochemistry
|July 14, 1987
Summary
N-methylated peptides reveal differences in protein kinase active sites. Backbone methylation can create selective peptide substrates and inhibitors for specific kinases like guanosine cyclic 3
Area of Science:
- Biochemistry
- Molecular Biology
- Enzymology
Background:
- N-methylated peptides serve as sensitive probes for substrate conformation in adenosine cyclic 3',5'-phosphate dependent protein kinase (A-kinase).
- While various protein kinases phosphorylate similar peptide sequences, their ability to differentiate substrates based on conformation remains largely uncharacterized.
Purpose of the Study:
- To investigate the substrate binding and conformational preferences of guanosine cyclic 3',5'-phosphate dependent protein kinase (G-kinase) using conformationally restricted N-methylated peptides.
- To determine if G-kinase differentiates between substrates based on conformation and to explore the potential of backbone methylation for kinase selectivity.
Main Methods:
- Utilized N-methylated peptides, previously shown to probe A-kinase active site conformation.
- Examined the interaction of these peptides with guanosine cyclic 3',5'-phosphate dependent protein kinase (G-kinase), an enzyme homologous to A-kinase.
Main Results:
- G-kinase appears to bind peptides in a conformation similar to A-kinase but exhibits greater tolerance for backbone methylation.
- A novel peptide substrate demonstrating at least 700-fold selectivity for G-kinase over A-kinase was identified.
Conclusions:
- Backbone methylation of peptides can be employed to confer selectivity for specific protein kinases.
- This strategy offers a potential method for developing selective peptide substrates and inhibitors for kinases like G-kinase and A-kinase.