diff --git a/src/DockQ/parsers.py b/src/DockQ/parsers.py
index 7135422..d63db71 100644
--- a/src/DockQ/parsers.py
+++ b/src/DockQ/parsers.py
@@ -208,7 +208,7 @@ def _build_structure(self, structure_id, chains, parse_hetatms):
                     resname1 = (
                         seq1(current_resname, custom_map=custom_map)
                         if len(current_resname) == 3
-                        else current_resname[:-1]
+                        else current_resname[-1]
                         if (len(current_resname) == 2)
                         else current_resname
                     )
@@ -432,7 +432,7 @@ def _parse_coordinates(self, coords_trailer, chains=[], parse_hetatms=False):
                             resname1 = (
                                 seq1(current_resname, custom_map=custom_map)
                                 if len(current_resname) == 3
-                                else current_resname[:-1]
+                                else current_resname[-1]
                                 if (len(current_resname) == 2)
                                 else current_resname
                             )
@@ -453,7 +453,7 @@ def _parse_coordinates(self, coords_trailer, chains=[], parse_hetatms=False):
                             resname1 = (
                                 seq1(current_resname, custom_map=custom_map)
                                 if len(current_resname) == 3
-                                else current_resname[:-1]
+                                else current_resname[-1]
                                 if (len(current_resname) == 2)
                                 else current_resname
                             )