Structural transitions in orb2 prion-like domain relevant for functional aggregation in memory consolidation

Javier Oroz, Sara S. Félix, Eurico J. Cabrita, Douglas V. Laurents

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

The recent structural elucidation of ex vivo Drosophila Orb2 fibrils revealed a novel amyloid formed by interdigitated Gln and His residue side chains belonging to the prion-like domain. However, atomic-level details on the conformational transitions associated with memory consolidation remain unknown. Here, we have characterized the nascent conformation and dynamics of the prion-like domain (PLD) of Orb2A using a nonconventional liquid-state NMR spectroscopy strategy based on 13C detection to afford an essentially complete set of 13Ca, 13Cb, 1Ha, and backbone 13CO and 15N assignments. At pH 4, where His residues are protonated, the PLD is disordered and flexible, except for a partially populated a-helix spanning residues 55–60, and binds RNA oligos, but not divalent cations. At pH 7, in contrast, His residues are predominantly neutral, and the Q/H segments adopt minor populations of helical structure, show decreased mobility and start to self-associate. At pH 7, the His residues do not bind RNA or Ca21, but do bind Zn21, which promotes further association. These findings represent a remarkable case of structural plasticity, based on which an updated model for Orb2A functional amyloidogenesis is suggested.

Original languageEnglish
Pages (from-to)18122-18133
Number of pages12
JournalJournal of Biological Chemistry
Volume295
Issue number52
DOIs
Publication statusPublished - 25 Dec 2020

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