diff --git a/python/obitools3/commands/export.pyx b/python/obitools3/commands/export.pyx
index 50f1c9f..d64450c 100644
--- a/python/obitools3/commands/export.pyx
+++ b/python/obitools3/commands/export.pyx
@@ -48,6 +48,8 @@ def run(config):
     DEFINITION_COLUMN = "DEFINITION"
     QUALITY_COLUMN = "QUALITY"    
     
+    special_columns = [NUC_SEQUENCE_COLUMN, ID_COLUMN, DEFINITION_COLUMN, QUALITY_COLUMN]
+    
     # Open DMS
     d = OBIDMS(config['obi']['defaultdms'])
     
@@ -64,7 +66,7 @@ def run(config):
         toprint = ">"+seq.get_id()+" "
         
         for col_name in seq :
-            if col_name != NUC_SEQUENCE_COLUMN and col_name != ID_COLUMN and col_name != DEFINITION_COLUMN and col_name != QUALITY_COLUMN :
+            if col_name not in special_columns :
                 toprint = toprint + col_name + "=" + str(seq[col_name]) + "; "
         
         if DEFINITION_COLUMN in seq :