Rational design of a SHP-2 targeted, fluorogenic peptide substrate.

Area of Science:

• Biochemistry
• Enzymology
• Chemical Biology

Background:

• Protein tyrosine phosphatases (PTPs) are crucial enzymes involved in cell signaling.
• Developing specific peptide-based probes for individual PTPs presents significant challenges.
• SHP-2 is a key PTP implicated in various cellular processes.

Purpose of the Study:

• To rationally design a fluorogenic peptide substrate targeting the SHP-2 enzyme.
• To establish a tool for monitoring PTP activity with improved specificity.
• To investigate the structure-activity relationship of peptide substrates for PTPs.

Main Methods:

• Design of a fluorogenic peptide substrate incorporating a phosphotyrosine mimetic (pCAP).
• Optimization of amino acid sequences surrounding the pCAP residue.
• Kinetic characterization of the designed peptide substrate using enzyme assays.
• Assessment of substrate selectivity against other PTPs.

Main Results:

• A novel SHP-2 targeted peptide substrate (Ac-DDPI-pCAP-DVLD-NH2) was successfully synthesized.
• Optimized substrate exhibited significantly improved kinetic parameters (kcat/Km = 270 M^-1s^-1) compared to pCAP alone.
• The peptide substrate demonstrated selectivity for SHP-2 over other tested PTPs (HePTP, MEG1, PTPμ).

Conclusions:

• Rational design and sequence optimization are effective strategies for creating specific PTP-targeted peptide substrates.
• The developed fluorogenic peptide probe serves as a valuable tool for studying SHP-2 activity.
• This approach can be extended to develop targeted probes for other PTP family members.