Does anybody knows a software or already build up module in python that calculates distance between protein and ligand C atoms.

The point is that I have a PDB file that has protein binding pocket atom coordinates, together with the number of 10 different ligand coordinates in. Something like this:

ATOM      1  N   VAL A   1      16.084  31.820  28.427  1.00 27.25           N  
ATOM      2  CA  VAL A   1      14.861  30.935  28.224  1.00 25.37           C  
ATOM      3  C   VAL A   1      14.253  31.406  26.892  1.00 22.19           C  
ATOM      4  O   VAL A   1      14.324  32.566  26.580  1.00 23.58           O  
ATOM      5  CB  VAL A   1      13.842  31.151  29.349  1.00 27.51           C  
ATOM      6  CG1 VAL A   1      12.499  30.433  29.111  1.00 26.28           C  
...
TER
HETATM 1539  C   3TZ A 187       4.075  12.355  25.223  1.00 35.58           C  
HETATM 1540  N   3TZ A 187       1.696  11.836  25.442  1.00 40.54           N  
HETATM 1541  O   3TZ A 187       5.202  11.813  25.232  1.00 33.14           O  
HETATM 1542  N1  3TZ A 187      -3.584  17.685  22.560  1.00 13.51           N 
...
TER
HETATM 1547  C6  2JP A 102      -3.679  17.145  23.785  1.00 15.83           C  
HETATM 1548  O6  2JP A 102      -4.191  15.926  23.690  1.00 19.66           O  
HETATM 1549  CA  2JP A 102       3.015  11.233  25.256  1.00 38.90           C  
HETATM 1550  CB  2JP A 102       3.172  10.552  23.884  1.00 41.37           C  
...
TER

etc, there are coordinates for 10 different ligands.

What I am interested in is to see for any C atom in each ligand, within distance of 4 Angstroms, how many protein C atoms would be identified? So that the final conclusion is: within 4A distance from ligand C atoms for all 10 ligands there are 35 protein C atoms identified.