Single-pass membrane protein

Source: Wikipedia, the free encyclopedia.
(Redirected from
Type I membrane 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

respiratory chain. A 2013 estimate identified about 1300 single-pass membrane proteins in the human genome.[4]

Topology-based classification

See also: Transmembrane protein § Classification by topology

Bitopic proteins are classified into 4 types, depending on their

Uniprot
:

  • Type I: N-terminus on the extracellular side of the membrane; removed signal peptide[5]
  • Type II: N-terminus on the cytoplasmic side of the membrane; transmembrane helix located close to the N-terminus, where it works as an anchor[6]
  • Type III: N-terminus on the extracellular side of the membrane; no signal peptide[7]
  • Type IV: N-terminus on the cytoplasmic side of the membrane; transmembrane helix located close to the C-terminus, where it works as an anchor[8]

Hence type I proteins are anchored to the lipid membrane with a stop-transfer anchor sequence and have their N-terminal domains targeted to the ER lumen during synthesis. Type II and III are anchored with a signal-anchor sequence, with type II being targeted to the ER lumen with its C-terminal domain, while type III have their N-terminal domains targeted to the ER lumen.

Structure

A single-pass transmembrane protein typically consists of three domains, the

disorder.[9] Some proteins in this class function as monomers, but dimerization or higher-order oligomerization is common.[9][10]

Evolution

The number of single-pass transmembrane proteins in an organism's

mammalian lineages.[4]

Databases

References

  1. ^ "Single-pass membrane protein". www.uniprot.org.
  2. ^ Membrane Structural Biology: With Biochemical and Biophysical Foundations, by Mary Luckey, 2014, Cambridge University Press, page 91.
  3. PMID 17258687
    .
  4. ^
    doi:10.1002/9780470015902.a0025160
    .
  5. ^ "Single-pass type I membrane protein". UniProt. Retrieved 15 June 2021.
  6. ^ "Single-pass type II membrane protein". UniProt. Retrieved 15 June 2021.
  7. ^ "Single-pass type III membrane protein". UniProt. Retrieved 15 June 2021.
  8. ^ "Single-pass type IV membrane protein". UniProt. Retrieved 15 June 2021.
  9. ^
    doi:10.1111/febs.13793
    .
  10. PMC 5487282
    .
  11. doi:10.1016/j.bbamem.2017.11.002
    .
Retrieved from "https://en.wikipedia.org/w/index.php?title=Single-pass_membrane_protein&oldid=1192813111"