Structural Analysis of the Menangle Virus P Protein Reveals a Soft Boundary between Ordered and Disordered Regions.

Melissa N Webby,Jeremy R Keown,David C Goldstone,Esther M M Bulloch,Nicole Herr,Richard L Kingston,Michael Schmitz

doi:10.3390/v13091737

Abstract

The paramyxoviral phosphoprotein (P protein) is the non-catalytic subunit of the viral RNA polymerase, and coordinates many of the molecular interactions required for RNA synthesis. All paramyxoviral P proteins oligomerize via a centrally located coiled-coil that is connected to a downstream binding domain by a dynamic linker. The C-terminal region of the P protein coordinates interactions between the catalytic subunit of the polymerase, and the viral nucleocapsid housing the genomic RNA. The inherent flexibility of the linker is believed to facilitate polymerase translocation. Here we report biophysical and structural characterization of the C-terminal region of the P protein from Menangle virus (MenV), a bat-borne paramyxovirus with zoonotic potential. The MenV P protein is tetrameric but can dissociate into dimers at sub-micromolar protein concentrations. The linker is globally disordered and can be modeled effectively as a worm-like chain. However, NMR analysis suggests very weak local preferences for alpha-helical and extended beta conformation exist within the linker. At the interface between the disordered linker and the structured C-terminal binding domain, a gradual disorder-to-order transition occurs, with X-ray crystallographic analysis revealing a dynamic interfacial structure that wraps the surface of the binding domain.

Highlights

The Paramyxoviruses are a large family of negative-sense, non-segmented, singlestranded RNA viruses
The paramyxoviral P protein is an integral component of the viral RNA-dependent RNA polymerase (RdRp) and its C-terminal region enables the RdRp to engage with the viral nucleocapsid
We have investigated the biophysical and structural characteristics of the C-terminal region of the P protein from Menangle virus, a bat borne pararubulavirus

Summary

Introduction

The Paramyxoviruses are a large family of negative-sense, non-segmented, singlestranded RNA viruses. Paramyxoviruses enter the host via the respiratory tract; infect most vertebrate species; and cause serious disease in both humans and animals. Pteropodid bats are the natural host for Hendra and Nipah viruses, which have spilled over into human and animal populations numerous times in the past three decades [3,4]. While Hendra and Nipah viruses cause no apparent disease in bats, they are highly pathogenic when transmitted to other animal populations, where they can cause fatal encephalitis [5]. Bats host many other paramyxoviruses with zoonotic potential. Among these is Menangle virus (MenV) [6,7], a pararubulavirus that was first identified following a novel disease outbreak in domesticated pigs [8]

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