Download MendeleyConformational motions and ligand-binding underlying gating and regulation in IP 3 R channel.
Fan, G., Baker, M.R., Terry, L.E., Arige, V., Chen, M., Seryshev, A.B., Baker, M.L., Ludtke, S.J., Yule, D.I., Serysheva, I.I.(2022) Nat Commun 13: 6942-6942
- PubMed: 36376291
- DOI: https://doi.org/10.1038/s41467-022-34574-1
- Primary Citation of Related Structures:
8EAQ, 8EAR - PubMed Abstract:
Inositol-1,4,5-trisphosphate receptors (IP 3 Rs) are activated by IP 3 and Ca 2+ and their gating is regulated by various intracellular messengers that finely tune the channel activity. Here, using single particle cryo-EM analysis we determined 3D structures of the nanodisc-reconstituted IP 3 R1 channel in two ligand-bound states. These structures provide unprecedented details governing binding of IP 3 , Ca 2+ and ATP, revealing conformational changes that couple ligand-binding to channel opening. Using a deep-learning approach and 3D variability analysis we extracted molecular motions of the key protein domains from cryo-EM density data. We find that IP 3 binding relies upon intrinsic flexibility of the ARM2 domain in the tetrameric channel. Our results highlight a key role of dynamic side chains in regulating gating behavior of IP 3 R channels. This work represents a stepping-stone to developing mechanistic understanding of conformational pathways underlying ligand-binding, activation and regulation of the channel.
Organizational Affiliation:
Department of Biochemistry and Molecular Biology, Structural Biology Imaging Center, McGovern Medical School at The University of Texas Health Science Center at Houston, 6431, Fannin Street, Houston, TX, USA.
