UNIT 5.2 Determining the Topology of an Integral Membrane Protein

  1. Neil Green1,
  2. Hong Fang1,
  3. Kai-Uwe Kalies2,
  4. Victor Canfield3

Published Online: 1 MAY 2001

DOI: 10.1002/0471143030.cb0502s00

Current Protocols in Cell Biology

Current Protocols in Cell Biology

How to Cite

Green, N., Fang, H., Kalies, K.-U. and Canfield, V. 2001. Determining the Topology of an Integral Membrane Protein. Current Protocols in Cell Biology. 00:5.2:5.2.1–5.2.27.

Author Information

  1. 1

    Vanderbilt University School of Medicine, Nashville, Tennessee

  2. 2

    Max Delbruck Center for Molecular Medicine, Berlin, Germany

  3. 3

    Pennsylvania State University College of Medicine, Hershey, Pennsylvania

Publication History

  1. Published Online: 1 MAY 2001
  2. Published Print: JAN 2000


A variety of methods have been developed for assigning the aqueous domains of integral membrane proteins to either side of a biological membrane. Once the sequence of a protein is known from its DNA sequence it is possible to study the topology of the protein. This unit provides protocols in which the water-soluble domains can be tested for their accessibility to reagents added to membranes with a defined orientation. Tagging of hydrophilic regions of the protein with different epitopes and probing of their orientation with respect to the membrane is also described. Finally, a procedure for fusion of a reporter enzyme to truncated fragments of the protein is provided. The fusion protein is used as a sensor of sequence disposition relative to the membrane.