Connexin: Difference between revisions
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=Structure:= | =Structure:= | ||
==Connexin structure== | ==Connexin structure== | ||
<scene name='70/701426/Connexin_structure2/1'>connexins</scene> are integral transmembranal proteins which consist of α-helical domains in the <scene name='70/701426/Tm1-tm4/1'>transmembrane segments</scene> (TM1-TM4), <scene name='70/701426/E1_and_e2/1'>two extracellular loops</scene> (E1 and E2), a cytoplasmic loop, an N-terminal helix (NTH), and a C-terminal segment. Each connexin consists of 227 amino acids, and <scene name='70/701426/Conxoxn_structure/1'>Six connexins</scene> form a hexamerical assembly, known as <scene name='70/701426/Connexin_26_basic_structure/3'>a connexon or hemmichannel</scene>, which delineates <scene name='70/701426/Pore/1'>an aqueous pore</scene> with a minimum diameter of ∼1.2 nm. When two hemichannels from adjacent cells dock and join, leaving a gap of ∼2–3 nm, they may form <scene name='70/701426/Connexin_26_basic_structure/5'>an intracellular pore or gap channel</scene> which spans the two plasma membranes and allows the exchange of cytoplasmic molecules with size up to ∼1 kDa. | |||
<scene name='70/701426/Connexin_structure2/1'>connexins</scene>are integral transmembranal proteins which consist of α-helical domains in the <scene name='70/701426/Tm1-tm4/1'>transmembrane segments</scene> (TM1-TM4) , <scene name='70/701426/E1_and_e2/1'>two extracellular loops</scene> (E1 and E2), a cytoplasmic loop, an N-terminal helix (NTH), and a C-terminal segment. Each connexin consists of 227 amino acids , and <scene name='70/701426/Conxoxn_structure/1'>Six connexins</scene> form a hexamerical assembly, known as <scene name='70/701426/Connexin_26_basic_structure/3'>a connexon or hemmichannel</scene>, which delineates <scene name='70/701426/Pore/1'>an aqueous pore</scene> with a minimum diameter of ∼1.2 nm. When two hemichannels from adjacent cells dock and join, leaving a gap of ∼2–3 nm, they may form <scene name='70/701426/Connexin_26_basic_structure/5'>an intracellular pore or gap channel</scene> which spans the two plasma membranes and allows the exchange of cytoplasmic molecules with size up to ∼1 kDa. | |||
The height of the modelled structure of the gap junction channel without disordered cytoplasmic loop and C-terminal segment is approximately 155Å.<ref name='Structure'/> [[Image:distances a.jpg | thumb | 350px |center]] | The height of the modelled structure of the gap junction channel without disordered cytoplasmic loop and C-terminal segment is approximately 155Å.<ref name='Structure'/> [[Image:distances a.jpg | thumb | 350px |center]] | ||