M2 Proton Channel: Difference between revisions
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== Structure == | == Structure == | ||
The M2 proton channel from influenza A is 97 amino acid residues and forms a 24-residue N-terminal extracellular domain, a 19-residue trans-membrane domain, and a 54-residue C-terminal cytoplasmic domain.<ref name="Wu" /> The 19-residue TM domain forms the highly selective proton channel.<ref name="Takeuchi">PMID:12972149 </ref> Circular dichroism spectra has shown the TM domain to form an <scene name='User:Sarah_Henke/Sandbox_1/Momomer/2'>α-helix</scene> that spans the membrane.<ref name="Wu" /> By analytical ultracentrifugation, the TM domain is found to form <scene name='User:Sarah_Henke/Sandbox_1/Alpha_hlix/1'>homotetramers</scene> which contains four identical α-helices.<ref name="Takeuchi" /> Secondary structure is coded by the following, if present: {{Template:ColorKey_Helix}}, {{Template:ColorKey_Strand}}, and {{Template:ColorKey_Turn}}. When viewed in the <scene name='User:Sarah_Henke/Sandbox_1/N_to_c/1'>N->C color coding</scene> the <FONT COLOR="blue">'''N-terminus'''</FONT> is located near the external side of the membrane while the <FONT COLOR="red">'''C-terminus'''</FONT> is located near the internal side of the membrane, closest to the virion. This tetrameric bundle of the TM domain is found by NMR to be tilted by 25-38° from the channel axis.<ref name="Takeuchi" /> The tetrameric helices form a left-handed bundle that resembles a truncated cone.<ref name="Stouffer" /> The TM helicies are arranged around the channel pore with an approximate four-fold rotational symmetry.<ref name="Takeuchi" /> | The M2 proton channel from influenza A is 97 amino acid residues and forms a 24-residue N-terminal extracellular domain, a 19-residue trans-membrane domain, and a 54-residue C-terminal cytoplasmic domain.<ref name="Wu" /> The 19-residue TM domain forms the highly selective proton channel.<ref name="Takeuchi">PMID:12972149 </ref> Circular dichroism spectra has shown the TM domain to form an <scene name='User:Sarah_Henke/Sandbox_1/Momomer/2'>α-helix</scene> that spans the membrane.<ref name="Wu" /> By analytical ultracentrifugation, the TM domain is found to form <scene name='User:Sarah_Henke/Sandbox_1/Alpha_hlix/1'>homotetramers</scene> which contains four identical α-helices.<ref name="Takeuchi" /> Secondary structure is coded by the following, if present: {{Template:ColorKey_Helix}}, {{Template:ColorKey_Strand}}, and {{Template:ColorKey_Turn}}. When viewed in the <scene name='User:Sarah_Henke/Sandbox_1/N_to_c/1'>N->C color coding</scene> the <FONT COLOR="blue">'''N-terminus'''</FONT> is located near the external side of the membrane while the <FONT COLOR="red">'''C-terminus'''</FONT> is located near the internal side of the membrane, closest to the virion. This tetrameric bundle of the TM domain is found by NMR to be tilted by 25-38° from the channel axis.<ref name="Takeuchi" /> The tetrameric helices form a left-handed bundle that resembles a truncated cone.<ref name="Stouffer" /> The TM helicies are arranged around the channel pore with an approximate four-fold rotational symmetry.<ref name="Takeuchi" /> | ||
{{Template:ColorKey_N2CRainbow}} | |||
== Central Cavity == | == Central Cavity == | ||