6LMX

Cryo-EM structure of the CALHM chimeric construct (9-mer)

Summary for 6LMX

• Entry DOI: 10.2210/pdb6lmx/pdb
• EMDB information: 0923
• Descriptor: Calcium homeostasis modulator 1,Calcium homeostasis modulator protein 2 (1 entity in total)
• Functional Keywords: channel, membrane protein
• Biological source: Oryzias latipes (Japanese rice fish); More
• Total number of polymer chains: 9
• Total formula weight: 336754.83

Authors

Demura, K.,Kusakizako, T.,Shihoya, W.,Hiraizumi, M.,Shimada, H.,Yamashita, K.,Nishizawa, T.,Nureki, O. (deposition date: 2019-12-26, release date: 2020-07-29, Last modification date: 2024-10-23)

Primary citation

Demura, K.,Kusakizako, T.,Shihoya, W.,Hiraizumi, M.,Nomura, K.,Shimada, H.,Yamashita, K.,Nishizawa, T.,Taruno, A.,Nureki, O.
Cryo-EM structures of calcium homeostasis modulator channels in diverse oligomeric assemblies.
Sci Adv, 6:eaba8105-eaba8105, 2020

PubMed Abstract: Calcium homeostasis modulator (CALHM) family proteins are Ca-regulated adenosine triphosphate (ATP)-release channels involved in neural functions including neurotransmission in gustation. Here, we present the cryo-electron microscopy (EM) structures of killifish CALHM1, human CALHM2, and CLHM-1 at resolutions of 2.66, 3.4, and 3.6 Å, respectively. The CALHM1 octamer structure reveals that the N-terminal helix forms the constriction site at the channel pore in the open state and modulates the ATP conductance. The CALHM2 undecamer and CLHM-1 nonamer structures show the different oligomeric stoichiometries among CALHM homologs. We further report the cryo-EM structures of the chimeric construct, revealing that the intersubunit interactions at the transmembrane domain (TMD) and the TMD-intracellular domain linker define the oligomeric stoichiometry. These findings advance our understanding of the ATP conduction and oligomerization mechanisms of CALHM channels.

PubMed: 32832629
DOI: 10.1126/sciadv.aba8105

Experimental method

ELECTRON MICROSCOPY (3.4 Å)