Structural characterization of the N-terminal part of the MERS-CoV nucleocapsid by X-ray diffraction and small-angle X-ray scattering

The N protein of coronaviruses is a multifunctional protein that is organized into several domains. The N‐terminal part is composed of an intrinsically disordered region (IDR) followed by a structured domain called the N‐terminal domain (NTD). In this study, the structure determination of the N‐terminal region of the MERS‐CoV N protein via X‐ray diffraction measurements is reported at a resolution of 2.4 Å. Since the first 30 amino acids were not resolved by X‐ray diffraction, the structural study was completed by a SAXS experiment to propose a structural model including the IDR. This model presents the N‐terminal region of the MERS‐CoV as a monomer that displays structural features in common with other coronavirus NTDs. The structural characterization of the N‐terminal part of the nucleocapsid from Middle East respiratory syndrome coronavirus (MERS‐CoV), a recently emerging virus, is reported. The structure of the N‐terminal region, which includes a disordered tail followed by a globular domain, was obtained by combining X‐ray diffraction and SAXS.