Transmembrane protein

Schematic representation of transmembrane proteins: 1) a single-pass membrane protein (α-helix) 2) a multipass membrane protein (α-helix) 3) a multipass membrane protein β-sheet. The membrane is represented in light yellow.

A transmembrane protein is a type of integral membrane protein that spans the entirety of the cell membrane. Many transmembrane proteins function as gateways to permit the transport of specific substances across the membrane. They frequently undergo significant conformational changes to move a substance through the membrane. They are usually highly hydrophobic and aggregate and precipitate in water. They require detergents or nonpolar solvents for extraction, although some of them (beta-barrels) can be also extracted using denaturing agents.

The peptide sequence that spans the membrane, or the transmembrane segment, is largely hydrophobic and can be visualized using the hydropathy plot.[1] Depending on the number of transmembrane segments, transmembrane proteins can be classified as single-pass membrane proteins, or as multipass membrane proteins.[2] Some other integral membrane proteins are called monotopic, meaning that they are also permanently attached to the membrane, but do not pass through it.[3]

  1. ^ Manor, Joshua; Feldblum, Esther S.; Arkin, Isaiah T. (2012). "Environment Polarity in Proteins Mapped Noninvasively by FTIR Spectroscopy". The Journal of Physical Chemistry Letters. 3 (7): 939–944. doi:10.1021/jz300150v. PMC 3341589. PMID 22563521.
  2. ^ Alberts, Bruce; Johnson, Alexander; Lewis, Julian; Raff, Martin; Roberts, Keith; Walter, Peter (2002). "Membrane Proteins". Molecular Biology of the Cell. 4th edition. Garland Science. Retrieved 31 October 2023.
  3. ^ Steven R. Goodman (2008). Medical cell biology. Academic Press. pp. 37–. ISBN 978-0-12-370458-0. Retrieved 24 November 2010.