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Controlled proteolysis of mouse epidermal growth factor. An RP-HPLC and 1H-n.m.r. study
E Menegatti1, S Scalia, F Bortolotti
1Department of Pharmaceutical Sciences, University of Ferrara, Italy.
Abstract:
Tryptic digestion of the mouse epidermal growth factor (mEGF) and the chromatographic separation of its proteolytic fragments by RP-HPLC affords the isolation of the pure hormone, of its 1-48 (Des(49-53)mEGF) and 1-45 (Des(46-53)mEGF) derivatives, and of the carboxyl-terminal pentapeptide W49-W50-E51-L52-R53. Kinetics of mEGF proteolytic degradation follows a two-state time-course: native mEGF being converted into Des(49-53)mEGF with an apparent half-time of 10 min; and Des(49-53)mEGF subsequently hydrolyzed to Des(46-53)mEGF with an apparent half-time of 7 h. Native mEGF and its proteolytic fragments have been characterized by 1H-n.m.r. spectroscopy. In the aromatic and aliphatic regions, the 1H-n.m.r. spectrum proved to be a sufficiently sensitive probe for following controlled proteolysis, and for analyzing the influence of the carboxyl-terminal sequence on the hormone conformation and stability.
Insights
Mouse epidermal growth factor (mEGF) undergoes tryptic digestion, yielding specific fragments. Proton nuclear magnetic resonance (1H-n.m.r.) spectroscopy effectively monitored this proteolysis and analyzed fragment stability.
Area of Science:
- Biochemistry
- Molecular Biology
- Protein Chemistry
Background:
- Mouse epidermal growth factor (mEGF) is a crucial signaling molecule.
- Understanding mEGF's proteolytic degradation is vital for its functional studies.
- Controlled proteolysis aids in characterizing protein structure and stability.
Purpose of the Study:
- To investigate the tryptic digestion products of mEGF.
- To characterize the kinetics of mEGF proteolytic degradation.
- To analyze the influence of the carboxyl-terminal sequence on mEGF conformation and stability using 1H-n.m.r. spectroscopy.
Main Methods:
- Tryptic digestion of mEGF.
- Reverse-phase high-performance liquid chromatography (RP-HPLC) for fragment separation.
- Proton nuclear magnetic resonance (1H-n.m.r.) spectroscopy for characterization.
Main Results:
- Isolation of pure mEGF, Des(49-53)mEGF, Des(46-53)mEGF, and the carboxyl-terminal pentapeptide.
- Two-state degradation kinetics observed: mEGF to Des(49-53)mEGF (t1/2 = 10 min) and Des(49-53)mEGF to Des(46-53)mEGF (t1/2 = 7 h).
- 1H-n.m.r. spectra sensitive to proteolysis, revealing conformational and stability influences of the carboxyl-terminal sequence.
Conclusions:
- Tryptic digestion yields defined mEGF fragments.
- The carboxyl-terminal region significantly impacts mEGF conformation and stability.
- 1H-n.m.r. spectroscopy is a valuable tool for studying protein proteolysis and structure-function relationships.