AWSEM Frustratometer examples

Loading Protein Structures

The AWSEM frustratometer package includes a prody-based Structure class to load the structure and calculate the properties needed for the AWSEM and DCA Frustratometers.

import frustratometer

# Define the path to your PDB file
pdb_path = Path('data/my_protein.pdb')
# Load the structure
structure = frustratometer.Structure.full_pdb(pdb_path)
structure.sequence #The sequence of the structure

Creating an AWSEM Model Instance

After loading the structure, create an AWSEM model instance with the desired parameters. Here we provide some typical configurations that can be found elsewhere.

## Single residue frustration with electrostatics
model_singleresidue = frustratometer.AWSEM(structure, min_sequence_separation_contact=2)
## Single residue frustration without electrostatics
model_singleresidue_noelectrostatics = frustratometer.AWSEM(structure, min_sequence_separation_contact=2, k_electrostatics=0)
## Mutational/Configurational frustration with electrostatics
model_mutational = frustratometer.AWSEM(structure)
## Mutational/Configurational frustration without electrostatics
model_mutational_noelectrostatics = frustratometer.AWSEM(structure, k_electrostatics=0)
## Mutational frustration with sequence separation of 12
model_mutational_seqsep12 = frustratometer.AWSEM(structure, min_sequence_separation_rho=13)
## Typical openAWSEM
model_openAWSEM = frustratometer.AWSEM(structure, min_sequence_separation_contact = 10, distance_cutoff_contact = None)

Calculating Residue Densities

To calculate the density of residues in the structure.

calculated_densities = model_singleresidue.rho_r
print(calculated_densities)

Calculating Frustration Indices

Frustration indices can be calculated for single residues or mutationally. This measurement helps identify energetically favorable or unfavorable interactions within the protein structure.

Single Residue Frustration

# Calculate single residue frustration
single_residue_frustration = model_singleresidue.frustration(kind='singleresidue')
print(single_residue_frustration)

Single Residue Decoy Fluctuation

The frustratometer package also allows the quick calculation of the energies of all single residue and mutational decoys.

# Calculate mutational frustration
mutational_frustration = model_singleresidue.decoy_fluctuation(kind='singleresidue')
print(mutational_frustration)

Mutational Frustration

# Calculate mutational frustration
mutational_frustration = model_mutational.frustration(kind='mutational')
print(mutational_frustration)

Energy Calculations

You can calculate different energy contributions, including fields energy (pseudo one-body terms like burial), couplings energy (pseudo two-body terms like contact and electrostatics), and their combination to determine the native energy of the protein structure.

Fields Energy

fields_energy = model_openAWSEM.fields_energy()
print(fields_energy)

Couplings Energy

couplings_energy = model_openAWSEM.couplings_energy()
print(couplings_energy)

Native Energy

Native energy can be considered as a combination of fields and couplings energy contributions.

native_energy = model_openAWSEM.native_energy()
print(native_energy)