Insights from Computational Dynamic Active Site Mapping into Substrate Recognition and Mutation-Induced Dysfunction...

Area of Science:

• Biochemistry
• Structural Biology
• Enzymology

Background:

• Human tyrosinase (Tyr) is crucial for melanin biosynthesis, processing diverse substrates like L-tyrosine and L-DOPA.
• The structural basis for Tyr's substrate selectivity and the impact of mutations are not well understood.

Purpose of the Study:

• To elucidate the structural and dynamic mechanisms underlying human tyrosinase's multi-substrate recognition.
• To investigate how disease-associated mutations affect Tyr's active site organization and dynamics.

Main Methods:

• Molecular docking and molecular dynamics simulations were employed to map the Tyr active site.
• Analysis focused on conserved residues, dynamic conformational responses, and the impact of specific mutations.

Main Results:

• Identified 23 conserved residues mediating multi-substrate binding through electrostatic and hydrophobic interactions.
• Observed coordinated conformational changes in anchoring and gating regions upon substrate binding.
• Demonstrated that the P406L mutation and other variants disrupt dynamic coupling and active-site organization.

Conclusions:

• Proposed an ordered multi-substrate binding mechanism involving specific anchoring, alignment, and refinement steps.
• Highlighted the dynamic network's sensitivity to genetic perturbations, impacting enzyme function.
• Provided a dynamic framework for understanding Tyr catalysis, mutation effects, and potential engineering strategies.