diff --git a/modules/io/doc/mmcif.rst b/modules/io/doc/mmcif.rst
index 0a6520a477378154df9096003133ff5d906cf43c..09404badf9f67765ad0980ac4f189d14948bf66c 100644
--- a/modules/io/doc/mmcif.rst
+++ b/modules/io/doc/mmcif.rst
@@ -601,7 +601,7 @@ of the annotation available.
 
     See :attr:`operationsintervalls`
 
-.. function:: PDBize(asu, seqres=None, min_polymer_size=10, transformation=False)
+  .. function:: PDBize(asu, seqres=None, min_polymer_size=10, transformation=False)
 
     Returns the biological assembly (bio unit) for an entity. The new entity
     created is well suited to be saved as a PDB file. Therefore the function