atom_order
==========

氨基酸所有原子名称及对应的索引值，键是原子名称，值是对应的索引。

+-----+-------+
| key | value |
+=====+=======+
| N   | 0     |
+-----+-------+
| CA  | 1     |
+-----+-------+
| C   | 2     |
+-----+-------+
| CB  | 3     |
+-----+-------+
| O   | 4     |
+-----+-------+
| CG  | 5     |
+-----+-------+
| CG1 | 6     |
+-----+-------+
| CG2 | 7     |
+-----+-------+
| OG  | 8     |
+-----+-------+
| OG1 | 9     |
+-----+-------+
| SG  | 10    |
+-----+-------+
| CD  | 11    |
+-----+-------+
| CD1 | 12    |
+-----+-------+
| CD2 | 13    |
+-----+-------+
| ND1 | 14    |
+-----+-------+
| ND2 | 15    |
+-----+-------+
| OD1 | 16    |
+-----+-------+
| OD2 | 17    |
+-----+-------+
| SD  | 18    |
+-----+-------+
| CE  | 19    |
+-----+-------+
| CE1 | 20    |
+-----+-------+
| CE2 | 21    |
+-----+-------+
| CE3 | 22    |
+-----+-------+
| NE  | 23    |
+-----+-------+
| NE1 | 24    |
+-----+-------+
| NE2 | 25    |
+-----+-------+
| OE1 | 26    |
+-----+-------+
| OE2 | 27    |
+-----+-------+
| CH2 | 28    |
+-----+-------+
| NH1 | 29    |
+-----+-------+
| NH2 | 30    |
+-----+-------+
| OH  | 31    |
+-----+-------+
| CZ  | 32    |
+-----+-------+
| CZ2 | 33    |
+-----+-------+
| CZ3 | 34    |
+-----+-------+
| NZ  | 35    |
+-----+-------+
| OXT | 36    |
+-----+-------+