Biophysical characterization of calcium-binding and modulatory-domain dynamics in a pentameric ligand-gated ion channel

Lycksell, MarieStockholms universitet,Institutionen för biokemi och biofysik,Science for Life Laboratory (SciLifeLab),Stockholm Univ, Sci Life Lab, Dept Biochem & Biophys, S-10691 Stockholm, Sweden. (författare)

QC 20230503
Pentameric ligand-gated ion channels (pLGICs) perform electrochemical signal transduction in organisms ranging from bacteria to humans. Among the prokaryotic pLGICs, there is architectural diversity involving N-terminal domains (NTDs) not found in eukaryotic relatives, exemplified by the calcium-sensitive channel (DeCLIC) from a Desulfofustis deltaproteobacterium, which has an NTD in addition to the canonical pLGIC structure. Here, we have characterized the structure and dynamics of DeCLIC through cryoelectron microscopy (cryo-EM), small-angle neutron scattering (SANS), and molecular dynamics (MD) simulations. In the presence and absence of calcium, cryo-EM yielded structures with alternative conformations of the calcium-binding site. SANS profiles further revealed conformational diversity at room temperature beyond that observed in static structures, shown through MD to be largely attributable to rigid-body motions of the NTD relative to the protein core, with expanded and asymmetric conformations improving the fit of the SANS data. This work reveals the range of motion available to the DeCLIC NTD and calcium-binding site, expanding the conformational landscape of the pLGIC family. Further, these findings demonstrate the power of combining low-resolution scattering, high-resolution structural, and MD simulation data to elucidate interfacial interactions that are highly conserved in the pLGIC family.

Rovšnik, UrškaStockholms universitet,Institutionen för biokemi och biofysik,Science for Life Laboratory (SciLifeLab),Stockholm Univ, Sci Life Lab, Dept Biochem & Biophys, S-10691 Stockholm, Sweden.(Swepub:su)urro0138 (författare)
Hanke, AntonStockholms universitet,Institutionen för biokemi och biofysik,Science for Life Laboratory (SciLifeLab),Stockholm Univ, Sci Life Lab, Dept Biochem & Biophys, S-10691 Stockholm, Sweden.;Heidelberg Univ, Inst Pharm & Mol Biotechnol, D-69120 Heidelberg, Germany. (författare)
Martel, AnneInst Laue Langevin, Large Scale Struct, F-38042 Grenoble, France. (författare)
Howard, Rebecca J.Stockholms universitet,Institutionen för biokemi och biofysik,Science for Life Laboratory (SciLifeLab),Stockholm Univ, Sci Life Lab, Dept Biochem & Biophys, S-10691 Stockholm, Sweden.(Swepub:su)rhowa (författare)
Lindahl, Erik,1972-KTH,Stockholms universitet,Institutionen för biokemi och biofysik,Science for Life Laboratory (SciLifeLab),KTH Royal Institute of Technology, Sweden,Science for Life Laboratory, SciLifeLab,Biofysik,Stockholm Univ, Sci Life Lab, Dept Biochem & Biophys, S-10691 Stockholm, Sweden.(Swepub:kth)u1u9f2s7 (författare)
Stockholms universitetInstitutionen för biokemi och biofysik (creator_code:org_t)

Ingår i:Proceedings of the National Academy of Sciences of the United States of America: Proceedings of the National Academy of Sciences119:500027-84241091-6490

Av författaren/redakt...: Lycksell, Marie; Rovšnik, Urška; Hanke, Anton; Martel, Anne; Howard, Rebecca ...; Lindahl, Erik, 1 ...

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