limiting to peptide search only

app.py

@@ -17,10 +17,12 @@ You can use it to search the full [PDB](https://www.rcsb.org/) database or in a
 """
 max_results = 1000
 choice_sep = " | "
+max_seq_length = 50
 
 
 def search_and_display(seq, max_res, index_selection):
     n_search_res = 10000
+    _validate_sequence_length(seq)
     max_res = int(limit_n_results(max_res))
     engine = engines[index_selection]
     search_res = engine.search_by_sequence(seq, n=n_search_res)
@@ -30,6 +32,11 @@ def search_and_display(seq, max_res, index_selection):
     return formatted_search_results, results_options
 
 
+def _validate_sequence_length(seq):
+    if len(seq) > max_seq_length:
+        raise gr.Error("Only peptide input is currently supported")
+
+
 def limit_n_results(n):
     return max(min(n, max_results), 1)