I am trying to determine the interaction of the targeted amino acid with other amino acids, but I am having trouble. When I pass a PDB file of a protein that has ligands, I can see the interactions. However, when I pass a PDB file of a protein without ligands, I don't see any interactions. Interestingly, when I run this ligand-free PDB file through LigPlot GUI, it shows the interactions.

PDB ID example: 1BBT

Here is the code I wrote:

filename = "1BBT.pdb"
ligPlotLoc = "LigPlus"
programLoc = f"{ligPlotLoc}/lib/exe_linux64/"
ligplot_prm = f"{ligPlotLoc}/lib/params/ligplot.prm"
atom_number = 82
chain_ID = 1

os.system(f"{programLoc}hbadd {filename} {ligPlotLoc}/components.cif -wkdir ./")
os.system(f"{programLoc}hbplus -L -f hbplus.rc -h 2.90 -d 3.90 -N {filename} -wkdir ./")
os.system(f"{programLoc}hbplus -L -f hbplus.rc -h 2.70 -d 3.35 {filename} -wkdir ./")
os.system(f"{programLoc}ligplot {filename} {atom_number} {atom_number} {chain_ID} -wkdir ./ -prm {ligplot_prm} -ctype 1")

Below is the image of the interaction I obtained from running the LigPlot command line.

Below is the interaction that I am trying to get using the LigPlot command line but haven't been able to. However, I successfully obtained it using the LigPlot GUI. But wanted to get it done through ligplot command