Antibody-antigen docs: mention that we always used the first bioassembly

PiperOrigin-RevId: 717556878

docs/metadata_antibody_antigen.md

@@ -1,9 +1,11 @@
-# Metadata for Antibody-Antigen pairs used to create figure 5a.
+# Metadata for Antibody-Antigen pairs used to create figure 5a
 
 Figure 5a in the AlphaFold 3 paper was created using 71 antibody–antigen
 complexes, containing 166 antibody–antigen interfaces spanning 65 interface
 clusters. Scores were averaged within each interface cluster then across
-clusters. We provide metadata for these complexes and the associated clusters in
-this CSV file:
+clusters. Note that the first bioassembly is used in all cases.
+
+We provide metadata for these complexes and the associated clusters in this CSV
+file:
 
 https://github.com/google-deepmind/alphafold3/blob/main/docs/metadata_antibody_antigen.csv