def read_molecule(r, line):
    '''Read a molecule from reader r.  The variable 'line'
    is the first line of the molecule to be read; the result is
    the molecule, and the first line after it (or the empty string
    if the end of file has been reached).'''

    fields = line.split()
    molecule = [fields[1]]

    line = r.readline()    
    while line and not line.startswith('COMPND'):
        fields = line.split()
        key, num, type, x, y, z = fields
        molecule.append((type, x, y, z))
        line = r.readline()

    return molecule, line

def read_all_molecules(r):
    '''Read zero or more molecules from reader r,
    returning a list of the molecules read.'''

    result = []
    line = r.readline()
    while line:
        molecule, line = read_molecule(r, line)
        result.append(molecule)
    return result

def main():
   myfile = open('multimol_no_ends.pdb','r')
   print(read_all_molecules(myfile))
   myfile.close() 

main()