diff --git a/kombu/transport/pyamqplib.py b/kombu/transport/pyamqplib.py
index 12bcd672..cbd35884 100644
--- a/kombu/transport/pyamqplib.py
+++ b/kombu/transport/pyamqplib.py
@@ -23,13 +23,14 @@ from amqplib.client_0_8.exceptions import AMQPConnectionException
 from amqplib.client_0_8.exceptions import AMQPChannelException
 
 from kombu.transport import base
+from kombu.utils.encoding import str_to_bytes
 
 DEFAULT_PORT = 5672
 
 # amqplib's handshake mistakenly identifies as protocol version 1191,
 # this breaks in RabbitMQ tip, which no longer falls back to
 # 0-8 for unknown ids.
-transport.AMQP_PROTOCOL_HEADER = "AMQP\x01\x01\x08\x00"
+transport.AMQP_PROTOCOL_HEADER = str_to_bytes("AMQP\x01\x01\x08\x00")
 
 
 class Connection(amqp.Connection):  # pragma: no cover