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==Estrutura==
Actualmente determináronse a resolción atómica as estruturas tridimensionais de só ~160 proteínas integrais de membrana por [[cristalografía de raios X]] ou [[espectroscopía]] de [[resonancia magnética nuclear]] debido ás dificultades da súa extracción e cristalización. Ademais, as estruturas de moitos domiios hidrosolubles das proteínas integrais están dispoñibles no [[Protein Data Bank]]. As súas [[hélice alfa|hélices α]] ancoradas na membrana fóronlles retiradas para facilitar a extracción e cristalización. [http://www.ebi.ac.uk/pdbe-srv/PDBeXplore/go/?GO=go:0016021 Proteínas integrais de membrana] que foron estudadas no PDB (baseadas na clasificación de [[ontoloxía de xenes]]).
Three-dimensional structures of only ~160 different integral membrane proteins are currently determined at atomic resolution by [[X-ray crystallography]] or [[nuclear magnetic resonance]] [[spectroscopy]] due to the difficulties with extraction and [[Crystallization adjutant|crystallization]]. In addition, structures of many water-soluble domains of IMPs are available in the [[Protein Data Bank]]. Their membrane-anchoring α-helices have been removed to facilitate the extraction and [[Protein crystallization|crystallization]]. Search [http://www.ebi.ac.uk/pdbe-srv/PDBeXplore/go/?GO=go:0016021 integral membrane proteins] in the PDB (based on [[gene ontology]] classification)
 
As proteínas integrais de membrana pode dividirse en dous grupos:
IMPs can be divided into two groups:
# [[Proteína integral politópica|Proteínas integrais politópicas]] (proteínas transmembrana).
# [[Transmembrane protein|Integral polytopic protein]]s (Transmembrane proteins)
# [[Proteína integral monotópica|proteínas integrais monotópicas]].
# [[Integral monotopic protein]]s
 
===IntegralProteína Polytopicintegeral Proteinpolitópica===
{{AP|Proteína transmembrana}}
{{Main|Transmembrane protein}}
The most common type of IMP is the [[transmembrane protein]] (TM), which spans the entire [[biological membrane]]. '''Single-pass''' membrane proteins cross the membrane only once, while '''multi-pass''' membrane proteins weave in and out, crossing several times. Single pass TM proteins can be categorized as Type I, which are positioned such that their carboxy-terminus is towards the [[cytosol]], or Type II, which have their amino-terminus towards the cytosol. Type III proteins have multiple transmembrane domains in a single polypeptide, while type IV consists of several different polypeptides assembled together in a channel through the membrane. Type V proteins are anchored to the lipid bilayer through covalently linked lipids. Finally Type VI proteins have both a transmembrane domains and lipid anchors.
<ref>Nelson, D. L., & Cox, M. M. (2008). Principles of Biochemistry (5th ed., p. 377). New York, NY: W.H. Freeman and Company.</ref>
Traído desde «https://gl.wikipedia.org/wiki/Proteína_integral_de_membrana»