chi_angles_mask
氨基酸中是否存在相应扭转角的mask，二维数组，第一维长度20，代表20种不同的氨基酸，与 restype_order 的顺序一致；第二维长度4，每个氨基酸最多有四个侧链扭转角，值为1.0代表该扭转角存在，0.0代表不存在。
value |
amino acid |
|||
|---|---|---|---|---|
0.0 |
0.0 |
0.0 |
0.0 |
#ALA |
1.0 |
1.0 |
1.0 |
1.0 |
#ARG |
1.0 |
1.0 |
0.0 |
0.0 |
#ASN |
1.0 |
1.0 |
0.0 |
0.0 |
#ASP |
1.0 |
0.0 |
0.0 |
0.0 |
#CYS |
1.0 |
1.0 |
1.0 |
0.0 |
#GLN |
1.0 |
1.0 |
1.0 |
0.0 |
#GLU |
0.0 |
0.0 |
0.0 |
0.0 |
#GLY |
1.0 |
1.0 |
0.0 |
0.0 |
#HIS |
1.0 |
1.0 |
0.0 |
0.0 |
#ILE |
1.0 |
1.0 |
0.0 |
0.0 |
#LEU |
1.0 |
1.0 |
1.0 |
1.0 |
#LYS |
1.0 |
1.0 |
1.0 |
0.0 |
#MET |
1.0 |
1.0 |
0.0 |
0.0 |
#PHE |
1.0 |
1.0 |
0.0 |
0.0 |
#PRO |
1.0 |
0.0 |
0.0 |
0.0 |
#SER |
1.0 |
0.0 |
0.0 |
0.0 |
#THR |
1.0 |
1.0 |
0.0 |
0.0 |
#TRP |
1.0 |
1.0 |
0.0 |
0.0 |
#TYR |
1.0 |
0.0 |
0.0 |
0.0 |
#VAL |