Packages the positive strand viral genome RNA into a helical ribonucleocapsid (RNP) and plays a fundamental role during virion assembly through its interactions with the viral genome and membrane protein M. Plays an important role in enhancing the efficiency of subgenomic viral RNA transcription as well as viral replication. Human coronavirus HKU1 (isolate N5) Nucleoprotein/NP Protein (His) is expressed in E. coli expression system with N-6xHis tag. The predicted molecular weight is 53.2 kDa and the accession number is Q0ZME3.