--- a
+++ b/tests/data/pdb/1ps3_zn.pdb
@@ -0,0 +1,54 @@
+HEADER    1PS3_POCKET
+COMPND    1PS3_POCKET
+REMARK    GENERATED BY X-TOOL on Tue Nov  8 15:57:05 2016
+ATOM      1  N   HIS A  90      36.796  61.054  14.930  1.00  7.46           N
+ATOM      2  H   HIS A  90      35.918  61.159  15.477  1.00  0.00           H
+ATOM      3  CA  HIS A  90      36.845  61.524  13.553  1.00  6.90           C
+ATOM      4  C   HIS A  90      37.506  62.900  13.475  1.00  7.03           C
+ATOM      5  O   HIS A  90      36.959  63.896  13.953  1.00  8.05           O
+ATOM      6  CB  HIS A  90      35.430  61.565  12.963  1.00  7.10           C
+ATOM      7  CG  HIS A  90      35.395  61.894  11.502  1.00  7.93           C
+ATOM      8  ND1 HIS A  90      35.998  61.109  10.541  1.00  7.77           N
+ATOM      9  CD2 HIS A  90      34.829  62.929  10.842  1.00  8.29           C
+ATOM     10  CE1 HIS A  90      35.803  61.649   9.351  1.00  8.70           C
+ATOM     11  NE2 HIS A  90      35.096  62.753   9.506  1.00  8.77           N
+TER      12      HIS A  90
+ATOM     13  N   ASP A  92      38.922  65.726  10.950  1.00  7.64           N
+ATOM     14  H   ASP A  92      38.342  66.212  11.664  1.00  0.00           H
+ATOM     15  CA  ASP A  92      38.980  66.259   9.594  1.00  8.08           C
+ATOM     16  C   ASP A  92      40.243  67.061   9.343  1.00  8.51           C
+ATOM     17  O   ASP A  92      40.520  68.015  10.064  1.00  9.16           O
+ATOM     18  CB  ASP A  92      37.782  67.165   9.332  1.00  7.68           C
+ATOM     19  CG  ASP A  92      36.488  66.407   9.296  1.00  8.50           C
+ATOM     20  OD1 ASP A  92      36.419  65.428   8.531  1.00  9.20           O
+ATOM     21  OD2 ASP A  92      35.548  66.791  10.028  1.00 11.07           O
+TER      22      ASP A  92
+ATOM     23  N   ASP A 204      32.993  58.753   6.720  1.00  7.04           N
+ATOM     24  H   ASP A 204      33.963  58.490   6.452  1.00  0.00           H
+ATOM     25  CA  ASP A 204      32.436  60.046   6.320  1.00  8.33           C
+ATOM     26  C   ASP A 204      32.339  60.449   4.837  1.00  7.67           C
+ATOM     27  O   ASP A 204      31.644  61.412   4.515  1.00  7.99           O
+ATOM     28  CB  ASP A 204      33.132  61.167   7.086  1.00  8.90           C
+ATOM     29  CG  ASP A 204      32.205  62.339   7.362  1.00  8.80           C
+ATOM     30  OD1 ASP A 204      32.707  63.465   7.490  1.00  9.75           O
+ATOM     31  OD2 ASP A 204      30.977  62.143   7.462  1.00  9.28           O
+TER      32      ASP A 204
+ATOM     33  N   HIS A 471      37.850  64.442   2.275  1.00  6.99           N
+ATOM     34  H   HIS A 471      38.079  63.878   3.118  1.00  0.00           H
+ATOM     35  CA  HIS A 471      36.456  64.607   1.876  1.00  7.35           C
+ATOM     36  C   HIS A 471      35.836  65.993   2.117  1.00  8.43           C
+ATOM     37  O   HIS A 471      34.624  66.165   1.966  1.00  7.41           O
+ATOM     38  CB  HIS A 471      35.573  63.511   2.498  1.00  6.98           C
+ATOM     39  CG  HIS A 471      35.695  63.394   3.981  1.00  6.97           C
+ATOM     40  ND1 HIS A 471      36.674  62.637   4.591  1.00  6.77           N
+ATOM     41  CD2 HIS A 471      34.963  63.939   4.980  1.00  8.52           C
+ATOM     42  CE1 HIS A 471      36.539  62.722   5.901  1.00  7.37           C
+ATOM     43  NE2 HIS A 471      35.509  63.505   6.163  1.00  8.69           N
+TER      44      HIS A 471
+HETATM   45 ZN   ZN      1      34.613  64.236   8.017  1.00  8.88          Zn
+CONECT   11   45
+CONECT   20   45
+CONECT   30   45
+CONECT   43   45
+CONECT   45   11   20   30   43
+END