Crystallographic analysis of the N-terminal domain of Middle East respiratory syndrome coronavirus nucleocapsid protein.

The N-terminal domain of the nucleocapsid protein from Middle East respiratory syndrome coronavirus (MERS-CoV NP-NTD) contains many positively charged residues and has been identified to be responsible for RNA binding during ribonucleocapsid formation by the virus. In this study, the crystallization and crystallographic analysis of MERS-CoV NP-NTD (amino acids 39-165), with a molecular weight of 14.7 kDa, are reported. MERS-CoV NP-NTD was crystallized at 293 K using PEG 3350 as a precipitant and a 94.5% complete native data set was collected from a cooled crystal at 77 K to 2.63 Å resolution with an overall Rmerge of 9.6%. The crystals were monoclinic and belonged to space group P21, with unit-cell parameters a = 35.60, b = 109.64, c = 91.99 Å, β = 101.22°. The asymmetric unit contained four MERS-CoV NP-NTD molecules.