diff --git a/pnas.csl b/pnas.csl
index 7fced43502..1f0bcf0290 100644
--- a/pnas.csl
+++ b/pnas.csl
@@ -29,7 +29,7 @@
     </names>
   </macro>
   <macro name="author">
-    <names variable="author" prefix=" ">
+    <names variable="author">
       <name name-as-sort-order="all" sort-separator=" " initialize-with="" delimiter=", " delimiter-precedes-last="always"/>
       <label form="short" prefix=" "/>
       <substitute>