Computational Studies of Catalytic Loop Dynamics in Yersinia Protein Tyrosine Phosphatase Using Pathway Optimization...

Area of Science:

• Biochemistry
• Computational Biology
• Enzymology

Background:

• Yersinia Protein Tyrosine Phosphatase (YopH) is a highly efficient enzyme.
• Enzyme function relies on catalytic loop movements for substrate binding and catalysis.
• Previous studies utilized fluorescence, NMR, and UV resonance Raman (UVRR) to investigate loop dynamics.

Purpose of the Study:

• To develop a computational approach for interpreting experimentally observed kinetic processes of YopH loop motions.
• To provide structural insights into the thermodynamic and dynamic properties of YopH's catalytic loop.
• To correlate computational findings with experimental kinetic data.

Main Methods:

• Developed a computational approach using pathway refinement methods: nudged elastic band (NEB) and harmonic Fourier beads (HFB).
• Determined minimum potential energy pathways for loop open/closure conformational changes using NEB.
• Calculated free energy barriers using HFB and estimated kinetic parameters via transition state theory.

Main Results:

• Established a correlation between computational energy barriers and experimentally observed enzyme dynamic rates after calibration.
• Assigned nanosecond kinetics to catalytic loop translational motion and microsecond kinetics to loop backbone dihedral angle flipping.
• Predicted a Trp354 conformational conversion on the tens of nanoseconds timescale.

Conclusions:

• The developed computational approach successfully provides structural interpretations for experimentally observed kinetic processes in YopH.
• Computational modeling can effectively elucidate the dynamic mechanisms underlying enzyme catalysis.
• Further experimental validation, such as UVRR T-jump studies, is suggested for predicted conformational changes.