Mechanism of Tetramer Dissociation, Unfolding, and Oligomer Assembly of Pneumovirus M2-1 Transcription Antiterminators.

ABSTRACT: Among Mononegavirales, the Pneumovirus family stands out by its RNA polymerase processivity that relies on a transcription antiterminator, the M2-1 protein, which also plays a key role in viral particle assembly. Biophysical and structural evidence shows that this RNA-binding tetramer is strongly modulated by a CCCH Zn²⁺ binding motif. We show that while the global dissociation/unfolding free energy is 10 kcal mol^-1, more stable for the respiratory syncytial virus M2-1, the human metapneumovirus (HMPV) counterpart shows a 7 kcal mol^-1 higher intersubunit affinity. Removal of Zn²⁺ from both homologues leads to an apo-monomer of identical secondary structure that further undergoes a slow irreversible oligomerization. Mutation of the histidine resid

SUBMITTER: Esperante SA 

PROVIDER: S-EPMC6289497 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature