diff --git a/modules/io/src/mol/pdb_writer.cc b/modules/io/src/mol/pdb_writer.cc
index 7b89e1f09cbfea8857fb9057285fcfd16f515c7f..670cf20893f4276076948addfb215372862a49fe 100644
--- a/modules/io/src/mol/pdb_writer.cc
+++ b/modules/io/src/mol/pdb_writer.cc
@@ -39,12 +39,14 @@ namespace {
 bool shift_left(const String& atom_name, bool is_hetatm, 
                 const String& element, float mass) 
 {
+  if (atom_name.length()==4) {
+    return true;
+  }
   if (is_hetatm==false) {
     return false;
   }
 
-  if (isdigit(atom_name[0]) || atom_name=="UNK" ||
-      atom_name.length()==4) {
+  if (isdigit(atom_name[0]) || atom_name=="UNK") {
     return true;
   }
   if (mass>34) {