Solvent accessible surface area of cysteine residues

cysteine_sasa.py

import numpy as np
import biotite.structure as struc
import biotite.structure.io.pdbx as pdbx
import biotite.database.rcsb as rcsb

path = rcsb.fetch("1aki", "pdbx", ".")
pdbx_file = pdbx.PDBxFile.read(path)
atoms = pdbx.get_structure(pdbx_file, model=1)
sasa_per_atom = struc.sasa(atoms)
sasa_per_residue = struc.apply_residue_wise(atoms, sasa_per_atom, np.nansum)
ids, names = struc.get_residues(atoms)
for atom_id, atom_name, sasa in zip(ids, names, sasa_per_residue):
    if atom_name == "CYS":
        print(f"SASA for {atom_name}{atom_id:<3d}: {sasa:6.2f} Ų" )

### Output ###
# SASA for CYS6  :  42.63 Ų
# SASA for CYS30 :   0.76 Ų
# SASA for CYS64 :   0.00 Ų
# SASA for CYS76 :   4.24 Ų
# SASA for CYS80 :   0.79 Ų
# SASA for CYS94 :   1.53 Ų
# SASA for CYS115:   0.00 Ų
# SASA for CYS127:  20.24 Ų