Key Interaction Changes Determine the Activation Process of Human Parathyroid Hormone Type 1 Receptor

Area of Science:

• Biochemistry
• Molecular Biology
• Pharmacology

Background:

• The parathyroid hormone type 1 receptor (PTH1R) is vital for physiological functions and a therapeutic target for osteoporosis.
• Limited molecular and energetic data hinder understanding of PTH1R activation mechanisms.

Purpose of the Study:

• To computationally explore PTH1R activation, including conformational changes, Gs protein coupling, and guanosine diphosphate (GDP) release.
• To identify kinetic information, such as rate-determining steps and energy barriers during PTH1R activation.
• To predict and validate significant residues and potential pathogenic mutations in PTH1R.

Main Methods:

• Utilized computational simulations to model PTH1R activation processes.
• Performed free-energy and structural analyses to understand molecular interactions.
• Employed site-directed mutagenesis to verify the significance of predicted residues.

Main Results:

• Identified key kinetic information, including the rate-determining step, transition state, and energy barriers for PTH1R activation.
• Revealed that guanosine diphosphate (GDP) release from the Gs protein occurs when the binding cavity is partially open.
• Predicted and experimentally validated important residues and potential pathogenic mutations within PTH1R.

Conclusions:

• Enhanced understanding of class B G protein-coupled receptor (GPCR) activation mechanisms, specifically for PTH1R.
• Provided insights into the molecular basis of PTH1R function and potential therapeutic interventions.
• Demonstrated the applicability of the employed computational methodology to other biophysical systems.