Entering edit mode
15 days ago
Nafi
•
0
I am having trouble in the following pdb: 1M7D pdb link.
The problem is: in chain A, after residue id 27 there are 5 other residues having seq numbers: 27A, 27B, 27C, 27D, 27E. Then after that 28 resumes normally. What is the reason for this? Does it signify any special thing?
The best way to find out is to read the original paper. My guess is that the residue has been crystallized in alternative conformations, which are signified by those A-E letters..
You can typically find much more useful info in the cif file, for example what you've found is called '_atom_site.pdbx_PDB_ins_code ' and described here; https://mmcif.wwpdb.org/dictionaries/mmcif_pdbx_v40.dic/Items/_atom_site.pdbx_PDB_ins_code.html
As Mensur Dlakic wrote, you'll need to read the paper for the context.