Editing Integral membrane protein (section)

===Integral monotopic proteins===
[[Image:Monotopic membrane protein.svg|thumb|right|400px|Schematic representation of the different types of interaction between monotopic membrane proteins and the [[cell membrane]]:
1. interaction by an amphipathic [[α-helix]] parallel to the membrane plane (in-plane membrane helix)
2. interaction by a hydrophobic loop
3. interaction by a covalently bound membrane lipid (''lipidation'')
4. electrostatic or [[Intermolecular forces#Ionic interactions|ionic interactions]] with membrane lipids (''e.g.'' through a calcium ion)]]

'''Integral monotopic proteins''' are permanently attached to the [[cell membrane]] from one side.<ref name="fowler">{{cite journal|last1=Fowler|first1=Philip W.|last2=Coveney|first2=Peter V.|title=A Computational Protocol for the Integration of the Monotopic Protein Prostaglandin H2 Synthase into a Phospholipid Bilayer|journal=Biophysical Journal|date=July 2006|volume=91|issue=2|pages=401–410|doi=10.1529/biophysj.105.077784|pmc=1483072|pmid=16632499|bibcode=2006BpJ....91..401F }}</ref>

Three-dimensional structures of the following integral monotopic proteins have been determined:{{cn|date=January 2025}}
* prostaglandin H2 syntheses 1 and 2 ([[cyclooxygenase]]s)
* [[lanosterol synthase]] and squalene-hopene cyclase
* microsomal [[prostaglandin E synthase]]
* [[carnitine O-palmitoyltransferase]] 2
* [[Undecaprenyl phosphate N,N'-diacetylbacillosamine 1-phosphate transferase|Phosphoglycosyl transferase C]]

There are also structures of integral monotopic ''domains'' of transmembrane proteins:{{cn|date=January 2025}}
* [[monoamine oxidase]]s A and B
* [[fatty acid amide hydrolase]]
* mammalian [[cytochrome P450 oxidase]]s
* [[11Beta Hydroxysteroid dehydrogenase|corticosteroid 11-beta-dehydrogenases]]