diff --git a/distributed/protocol/serialize.py b/distributed/protocol/serialize.py
index 4fa85d66a5..f97ba6dd3b 100644
--- a/distributed/protocol/serialize.py
+++ b/distributed/protocol/serialize.py
@@ -1,6 +1,6 @@
 from array import array
+from collections import deque
 from functools import partial
-from itertools import repeat
 import traceback
 import importlib
 from enum import Enum
@@ -445,34 +445,46 @@ def extract_serialize(x):
     >>> extract_serialize(msg)
     ({'op': 'update'}, {('data',): <Serialize: 123>}, set())
     """
-    x2 = type(x)()
-    ser = {}
-    bytestrings = set()
-    _extract_serialize(x, x2, ser, bytestrings)
-    return x2, ser, bytestrings
-
-
-def _extract_serialize(x, x2, ser, bytestrings, path=()):
     typ_x = type(x)
     if typ_x is dict:
         x_items = x.items()
+        x2 = {}
     elif typ_x is list:
         x_items = enumerate(x)
-        x2.extend(repeat(None, len(x)))
-
-    for k, v in x_items:
-        path_k = path + (k,)
-        typ_v = type(v)
-        if typ_v is dict or typ_v is list:
-            x2[k] = v2 = typ_v()
-            _extract_serialize(v, v2, ser, bytestrings, path_k)
-        elif typ_v is Serialize or typ_v is Serialized:
-            ser[path_k] = v
-        elif (typ_v is bytes or typ_v is bytearray) and len(v) > 2 ** 16:
-            ser[path_k] = to_serialize(v)
-            bytestrings.add(path_k)
+        x2 = len(x) * [None]
+
+    ser = {}
+    bytestrings = set()
+    _extract_serialize(x_items, x2, ser, bytestrings)
+    return x2, ser, bytestrings
+
+
+def _extract_serialize(x_items, x2, ser, bytestrings, path=()):
+    q = deque()
+    while True:
+        for k, v in x_items:
+            path_k = path + (k,)
+            typ_v = type(v)
+            if typ_v is dict:
+                v_items = v.items()
+                x2[k] = v2 = {}
+                q.append((v_items, v2, path_k))
+            elif typ_v is list:
+                v_items = enumerate(v)
+                x2[k] = v2 = len(v) * [None]
+                q.append((v_items, v2, path_k))
+            elif typ_v is Serialize or typ_v is Serialized:
+                ser[path_k] = v
+            elif (typ_v is bytes or typ_v is bytearray) and len(v) > 2 ** 16:
+                ser[path_k] = to_serialize(v)
+                bytestrings.add(path_k)
+            else:
+                x2[k] = v
+
+        if q:
+            x_items, x2, path = q.pop()
         else:
-            x2[k] = v
+            break
 
 
 def nested_deserialize(x):