GalaxyGPCRloop

GalaxyGPCRloop models the second extracellular loop (ECL2) of G-protein-coupled receptors (GPCRs) to predict ECL2 conformations relevant to GPCR function and drug discovery.

Key Features:

• Hybrid Approach: Integrates template-based and ab initio methods to address diverse ECL2 structural characteristics.
• Template-Based Sampling: Selects loop structure templates from existing databases for targets with similar ECL2s.
• Template Selection Metric: Applies a novel metric to evaluate similarity between target loops and available templates.
• Ab Initio Sampling: Employs fragment assembly and loop closure methods when highly similar templates are unavailable.
• Secondary Structure Prediction: Incorporates secondary structure prediction to enhance ab initio sampling.
• Disulfide Bridge Prediction and Constraint Incorporation: Predicts conserved disulfide bridges and analytically incorporates these constraints to reduce the conformational search dimensionality.
• Energy Function Integration: Integrates the developed sampling method with an existing energy function for comparative evaluation of predicted structures.

Scientific Applications:

• Structural Biology: Provides predicted ECL2 conformations to support studies of GPCR structure–function relationships.
• Pharmacology and Drug Discovery: Informs GPCR-related drug discovery by supplying ECL2 structural models relevant to ligand interactions and therapeutic targeting.

Methodology:

Uses template-based sampling with a novel template selection metric; ab initio sampling grounded in fragment assembly and loop closure; secondary structure prediction to guide sampling; prediction and analytical incorporation of conserved disulfide-bridge constraints; and integration of the sampling method with an existing energy function.