Download MendeleyMultiple sub-state structures of SERCA2b reveal conformational overlap at transition steps during the catalytic cycle.
Zhang, Y., Kobayashi, C., Cai, X., Watanabe, S., Tsutsumi, A., Kikkawa, M., Sugita, Y., Inaba, K.(2022) Cell Rep 41: 111760-111760
- PubMed: 36476867
- DOI: https://doi.org/10.1016/j.celrep.2022.111760
- Primary Citation of Related Structures:
7W7T, 7W7U, 7W7V, 7W7W - PubMed Abstract:
Sarco/endoplasmic reticulum Ca 2+ ATPase (SERCA) pumps Ca 2+ into the endoplasmic reticulum (ER). Herein, we present cryo-electron microscopy (EM) structures of three intermediates of SERCA2b: Ca 2+ -bound phosphorylated (E1P·2Ca 2+ ) and Ca 2+ -unbound dephosphorylated (E2·Pi) intermediates and another between the E2P and E2·Pi states. Our cryo-EM analysis demonstrates that the E1P·2Ca 2+ state exists in low abundance and preferentially transitions to an E2P-like structure by releasing Ca 2+ and that the Ca 2+ release gate subsequently undergoes stepwise closure during the dephosphorylation processes. Importantly, each intermediate adopts multiple sub-state structures including those like the next one in the catalytic series, indicating conformational overlap at transition steps, as further substantiated by atomistic molecular dynamic simulations of SERCA2b in a lipid bilayer. The present findings provide insight into how enzymes accelerate catalytic cycles.
Organizational Affiliation:
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan.
