Hi all
I have to build an homology model of a protein containing a residue (acetyl lysine) not included in the library. I considered this residue as an “unknown” residue (UNK in the pdb and X in the one letter code in the pir file) in the template. At the end of the modeler calculation i obtained a residue lacking of the side chain (just like a Glycine).
Which one-letter code (in the pir file) and tree-letters code (in the pdb file) should the acetyl lysine’s residue have to obtain a resulting model containing a complete and correct acetyl lysine?

Another question: i noticed that in the alignment window of DS you can change the letters of the sequence just by typing the letter of the keyboard. I’d like to consider a residue as blocked (BLK) in a modeler calculation and i’ve tried to substitute a letter of the alignment with a “.” as written in the restyp_accelrys.lib library. It seems that’s not possible to add a “.” in the sequence. Is there a way to run a calculation with a blocked (BLK) residue using the DS grahical interface?

Thanks in advance.

Davide