6BK9

Crystal Structure of Squid Arrestin

Summary for 6BK9

• Entry DOI: 10.2210/pdb6bk9/pdb
• Descriptor: Visual arrestin, CHLORIDE ION (2 entities in total)
• Functional Keywords: arrestin, phosphorylation independent, squid, invertebrate, rhodopsin, adapter protein, signaling protein
• Biological source: Doryteuthis pealeii (Longfin inshore squid)
• Total number of polymer chains: 1
• Total formula weight: 43009.57

Authors

Eger, B.T.,Bandyopadhyay, A.,Yedidi, R.S.,Ernst, O.P. (deposition date: 2017-11-08, release date: 2018-09-19, Last modification date: 2024-10-23)

Primary citation

Bandyopadhyay, A.,Van Eps, N.,Eger, B.T.,Rauscher, S.,Yedidi, R.S.,Moroni, T.,West, G.M.,Robinson, K.A.,Griffin, P.R.,Mitchell, J.,Ernst, O.P.
A Novel Polar Core and Weakly Fixed C-Tail in Squid Arrestin Provide New Insight into Interaction with Rhodopsin.
J. Mol. Biol., 430:4102-4118, 2018

PubMed Abstract: Photoreceptors of the squid Loligo pealei contain a G-protein-coupled receptor (GPCR) signaling system that activates phospholipase C in response to light. Analogous to the mammalian visual system, signaling of the photoactivated GPCR rhodopsin is terminated by binding of squid arrestin (sArr). sArr forms a light-dependent, high-affinity complex with squid rhodopsin, which does not require prior receptor phosphorylation for interaction. This is at odds with classical mammalian GPCR desensitization where an agonist-bound phosphorylated receptor is needed to break stabilizing constraints within arrestins, the so-called "three-element interaction" and "polar core" network, before a stable receptor-arrestin complex can be established. Biophysical and mass spectrometric analysis of the squid rhodopsin-arrestin complex indicates that in contrast to mammalian arrestins, the sArr C-tail is not involved in a stable three-element interaction. We determined the crystal structure of C-terminally truncated sArr that adopts a basal conformation common to arrestins and is stabilized by a series of weak but novel polar core interactions. Unlike mammalian arrestin-1, deletion of the sArr C-tail does not influence kinetic properties of complex formation of sArr with the receptor. Hydrogen-deuterium exchange studies revealed the footprint of the light-activated rhodopsin on sArr. Furthermore, double electron-electron resonance spectroscopy experiments provide evidence that receptor-bound sArr adopts a conformation different from the one known for arrestin-1 and molecular dynamics simulations reveal the residues that account for the weak three-element interaction. Insights gleaned from studying this system add to our general understanding of GPCR-arrestin interaction.

PubMed: 30120952
DOI: 10.1016/j.jmb.2018.08.009

Experimental method

X-RAY DIFFRACTION (3.00005573983 Å)