6F7A

Gloeobacter Ligand-gated Ion Channel (GLIC) closed state crystallized in an ultra-swollen lipidic mesophase

Summary for 6F7A

• Entry DOI: 10.2210/pdb6f7a/pdb
• Descriptor: Proton-gated ion channel (1 entity in total)
• Functional Keywords: transport protein, membrane protein
• Biological source: Gloeobacter violaceus (strain PCC 7421)
• Cellular location: Cell inner membrane ; Multi- pass membrane protein : Q7NDN8
• Total number of polymer chains: 5
• Total formula weight: 178210.21

Authors

Martiel, I.,Zabara, A.,Chong, J.Y.T.,Stark, L.,Cromer, B.,Dummond, C.J.,Mezzenga, R. (deposition date: 2017-12-07, release date: 2018-02-14, Last modification date: 2024-01-17)

Primary citation

Zabara, A.,Chong, J.T.Y.,Martiel, I.,Stark, L.,Cromer, B.A.,Speziale, C.,Drummond, C.J.,Mezzenga, R.
Design of ultra-swollen lipidic mesophases for the crystallization of membrane proteins with large extracellular domains.
Nat Commun, 9:544-544, 2018

PubMed Abstract: In meso crystallization of membrane proteins from lipidic mesophases is central to protein structural biology but limited to membrane proteins with small extracellular domains (ECDs), comparable to the water channels (3-5 nm) of the mesophase. Here we present a strategy expanding the scope of in meso crystallization to membrane proteins with very large ECDs. We combine monoacylglycerols and phospholipids to design thermodynamically stable ultra-swollen bicontinuous cubic phases of double-gyroid (Ia3d), double-diamond (Pn3m), and double-primitive (Im3m) space groups, with water channels five times larger than traditional lipidic mesophases, and showing re-entrant behavior upon increasing hydration, of sequences Ia3d→Pn3m→Ia3d and Pn3m→Im3m→Pn3m, unknown in lipid self-assembly. We use these mesophases to crystallize membrane proteins with ECDs inaccessible to conventional in meso crystallization, demonstrating the methodology on the Gloeobacter ligand-gated ion channel (GLIC) protein, and show substantial modulation of packing, molecular contacts and activation state of the ensued proteins crystals, illuminating a general strategy in protein structural biology.

PubMed: 29416037
DOI: 10.1038/s41467-018-02996-5

Experimental method

X-RAY DIFFRACTION (6 Å)