Transmembrane protein
Schematic representation of transmembrane proteins: 1. a protein with single transmembrane α-helix (a single-pass membrane protein) (bitopic) 2. a polytopic transmembrane α-helical protein 3. a polytopic transmembrane β-sheet protein The membrane is represented in yellow.
A single-pass membrane protein also known as single-spanning protein or bitopic protein is a transmembrane protein that spans the lipid bilayer only once.[ 1] [ 2] These proteins may constitute up to 50% of all transmembrane proteins , depending on the organism, and contribute significantly to the network of interactions between different proteins in cells , including interactions via transmembrane alpha helices .[ 3] They usually include one or several water-soluble domains situated at the different sides of biological membranes , for example in single-pass transmembrane receptors .[ 4] Some of them are small and serve as regulatory or structure-stabilizing subunits in large multi-protein transmembrane complexes, such as photosystems or the respiratory chain . More than 2300 single-pass membrane proteins were identified in the human genome .[ 5]
^ "Single-pass membrane protein" . www.uniprot.org .
^ Membrane Structural Biology: With Biochemical and Biophysical Foundations , by Mary Luckey, 2014, Cambridge University Press , page 91.
^ Zviling, Moti; Kochva, Uzi; Arkin, Isaiah T. (2007). "How important are transmembrane helices of bitopic membrane proteins?". Biochimica et Biophysica Acta (BBA) - Biomembranes . 1768 (3): 387–392. doi :10.1016/j.bbamem.2006.11.019 . PMID 17258687 .
^ Pahl, Matthew C; Askinazi, Olga L; Hamilton, Catherine; Cheng, Irene; Cichewicz, Karol; Kuhn, Jason; Manohar, Sumanth; Deppmann, Christopher D (2013-10-18). "Signalling via Single-Pass Transmembrane Proteins". eLS : a0025160. doi :10.1002/9780470015902.a0025160 .
^ List of single-pass transmembrane proteins in humans according to Membranome database