Like this:
HETATM 1519 C1 AAB1 B 100 -12.826 12.835 34.863 0.50 14.18 C
HETATM 1520 C1 BAB1 B 100 -4.549 17.796 20.909 0.50 14.18 C
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There is only one C1 atom in AB1, but now we have the A and B version of this. I guess that because of the X-ray crystallography method, which has diffraction. But I am not sure about that.
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written
by
ganuongphap •
1 answer
When interpreting the x-ray diffraction and its correspondent electron density map, sometimes the position the a particular atoms is not crystal clear (pun intended). The atom can be too mobile, the density particularly bad at in that region, etc.. it's also tied to the occupancy factor (the second to last column, 0.50 in your example) which is 1.00 if the atom is observed 100% of the time at one place, less if split between different locations. In these cases, you have multiple entries per location of the same atom, differentiated by the character at position 17.
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written
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João Rodrigues
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