7mit: Difference between revisions

From Proteopedia
Jump to navigation Jump to search
← Older edit
No edit summary
No edit summary
 
Line 12: Line 12:
<div style="background-color:#fffaf0;">
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
== Publication Abstract from PubMed ==
Vascular tone is dependent on smooth muscle KATP channels comprising pore-forming Kir6.1 and regulatory SUR2B subunits, in which mutations cause Cantu syndrome. Unique among KATP isoforms, they lack spontaneous activity and require Mg-nucleotides for activation. Structural mechanisms underlying these properties are unknown. Here, we determined cryogenic electron microscopy structures of vascular KATP channels bound to inhibitory ATP and glibenclamide, which differ informatively from similarly determined pancreatic KATP channel isoform (Kir6.2/SUR1). Unlike SUR1, SUR2B subunits adopt distinct rotational "propeller" and "quatrefoil" geometries surrounding their Kir6.1 core. The glutamate/aspartate-rich linker connecting the two halves of the SUR-ABC core is observed in a quatrefoil-like conformation. Molecular dynamics simulations reveal MgADP-dependent dynamic tripartite interactions between this linker, SUR2B, and Kir6.1. The structures captured implicate a progression of intermediate states between MgADP-free inactivated, and MgADP-bound activated conformations wherein the glutamate/aspartate-rich linker participates as mobile autoinhibitory domain, suggesting a conformational pathway toward KATP channel activation.
Vascular tone is dependent on smooth muscle K(ATP) channels comprising pore-forming Kir6.1 and regulatory SUR2B subunits, in which mutations cause Cantu syndrome. Unique among K(ATP) isoforms, they lack spontaneous activity and require Mg-nucleotides for activation. Structural mechanisms underlying these properties are unknown. Here, we determined cryogenic electron microscopy structures of vascular K(ATP) channels bound to inhibitory ATP and glibenclamide, which differ informatively from similarly determined pancreatic K(ATP) channel isoform (Kir6.2/SUR1). Unlike SUR1, SUR2B subunits adopt distinct rotational "propeller" and "quatrefoil" geometries surrounding their Kir6.1 core. The glutamate/aspartate-rich linker connecting the two halves of the SUR-ABC core is observed in a quatrefoil-like conformation. Molecular dynamics simulations reveal MgADP-dependent dynamic tripartite interactions between this linker, SUR2B, and Kir6.1. The structures captured implicate a progression of intermediate states between MgADP-free inactivated, and MgADP-bound activated conformations wherein the glutamate/aspartate-rich linker participates as mobile autoinhibitory domain, suggesting a conformational pathway toward K(ATP) channel activation.


Vascular KATP channel structural dynamics reveal regulatory mechanism by Mg-nucleotides.,Sung MW, Yang Z, Driggers CM, Patton BL, Mostofian B, Russo JD, Zuckerman DM, Shyng SL Proc Natl Acad Sci U S A. 2021 Nov 2;118(44). pii: 2109441118. doi:, 10.1073/pnas.2109441118. PMID:34711681<ref>PMID:34711681</ref>
Vascular K(ATP) channel structural dynamics reveal regulatory mechanism by Mg-nucleotides.,Sung MW, Yang Z, Driggers CM, Patton BL, Mostofian B, Russo JD, Zuckerman DM, Shyng SL Proc Natl Acad Sci U S A. 2021 Nov 2;118(44):e2109441118. doi: , 10.1073/pnas.2109441118. PMID:34711681<ref>PMID:34711681</ref>


From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

Latest revision as of 16:43, 6 November 2024

Vascular KATP channel: Kir6.1 SUR2B propeller-like conformation 1Vascular KATP channel: Kir6.1 SUR2B propeller-like conformation 1

Structural highlights

7mit is a 5 chain structure with sequence from Rattus norvegicus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:Electron Microscopy, Resolution 3.4Å
Ligands:, , , , , ,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

KCNJ8_RAT This potassium channel is controlled by G proteins. Inward rectifier potassium channels are characterized by a greater tendency to allow potassium to flow into the cell rather than out of it. Their voltage dependence is regulated by the concentration of extracellular potassium; as external potassium is raised, the voltage range of the channel opening shifts to more positive voltages. The inward rectification is mainly due to the blockage of outward current by internal magnesium. Can be blocked by external barium.[1]

Publication Abstract from PubMed

Vascular tone is dependent on smooth muscle K(ATP) channels comprising pore-forming Kir6.1 and regulatory SUR2B subunits, in which mutations cause Cantu syndrome. Unique among K(ATP) isoforms, they lack spontaneous activity and require Mg-nucleotides for activation. Structural mechanisms underlying these properties are unknown. Here, we determined cryogenic electron microscopy structures of vascular K(ATP) channels bound to inhibitory ATP and glibenclamide, which differ informatively from similarly determined pancreatic K(ATP) channel isoform (Kir6.2/SUR1). Unlike SUR1, SUR2B subunits adopt distinct rotational "propeller" and "quatrefoil" geometries surrounding their Kir6.1 core. The glutamate/aspartate-rich linker connecting the two halves of the SUR-ABC core is observed in a quatrefoil-like conformation. Molecular dynamics simulations reveal MgADP-dependent dynamic tripartite interactions between this linker, SUR2B, and Kir6.1. The structures captured implicate a progression of intermediate states between MgADP-free inactivated, and MgADP-bound activated conformations wherein the glutamate/aspartate-rich linker participates as mobile autoinhibitory domain, suggesting a conformational pathway toward K(ATP) channel activation.

Vascular K(ATP) channel structural dynamics reveal regulatory mechanism by Mg-nucleotides.,Sung MW, Yang Z, Driggers CM, Patton BL, Mostofian B, Russo JD, Zuckerman DM, Shyng SL Proc Natl Acad Sci U S A. 2021 Nov 2;118(44):e2109441118. doi: , 10.1073/pnas.2109441118. PMID:34711681[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. ↑ Inagaki N, Tsuura Y, Namba N, Masuda K, Gonoi T, Horie M, Seino Y, Mizuta M, Seino S. Cloning and functional characterization of a novel ATP-sensitive potassium channel ubiquitously expressed in rat tissues, including pancreatic islets, pituitary, skeletal muscle, and heart. J Biol Chem. 1995 Mar 17;270(11):5691-4. PMID:7890693
  2. ↑ Sung MW, Yang Z, Driggers CM, Patton BL, Mostofian B, Russo JD, Zuckerman DM, Shyng SL. Vascular KATP channel structural dynamics reveal regulatory mechanism by Mg-nucleotides. Proc Natl Acad Sci U S A. 2021 Nov 2;118(44). pii: 2109441118. doi:, 10.1073/pnas.2109441118. PMID:34711681 doi:http://dx.doi.org/10.1073/pnas.2109441118

7mit, resolution 3.40Å

Drag the structure with the mouse to rotate

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA
Retrieved from "https://proteopedia.openfox.io/wiki/index.php?title=7mit&oldid=4230472"