diff --git a/roi.yml b/roi.yml
new file mode 100644
index 0000000..2df43f0
--- /dev/null
+++ b/roi.yml
@@ -0,0 +1,41 @@
+regions:
+
+  site_1:
+    description: iodide_1
+    atoms:
+      - atom: I
+        res_name: IOD
+        chain: B
+        resid: 10
+
+  site_2:
+    description: iodide_2
+    atoms:
+      - atom: I
+        res_name: IOD
+        chain: B
+        resid: 12
+
+  site_3:
+    description: iodide_3
+    atoms:
+      - atom: I
+        res_name: IOD
+        chain: B
+        resid: 13
+
+  site_4:
+    description: iodide_4
+    atoms:
+      - atom: I
+        res_name: IOD
+        chain: B
+        resid: 14
+
+  site_5:
+    description: main_chain
+    atoms:
+      - atom: O
+        res_name: ARG
+        chain: A
+        resid: 73