Crystallization and preliminary X-ray diffraction analysis of the N-terminal domain of human coronavirus OC43 nucleocapsid protein

The N-terminal domain of nucleocapsid protein from human coronavirus OC43 (HCoV-OC43 N-NTD) mostly contains positively charged residues and has been identified as being responsible for RNA binding during ribonucleocapsid formation in the coronavirus. In this study, the crystallization and preliminary crystallographic analysis of HCoV-OC43 N-NTD (amino acids 58-195) with a molecular weight of 20 kDa are reported. HCoV-OC43 N-NTD was crystallized at 293 K using PEG 1500 as a precipitant and a 99.9% complete native data set was collected to 1.7 Å resolution at 100 K with an overall R_merge of 5.0%. The crystals belonged to the hexagonal space group P6₅, with unit-cell parameters a = 81.57, c = 42.87 Å. Solvent-content calculations suggest that there is likely to be one subunit of N-NTD in the asymmetric unit.