SDS-PAGE of full length SARS CoV-2 N 5′ 6X-HIS and N-terminal domain (NTD) 5′ 6X-HIS, produced in E. coli, and purified through HIS spin-columns. Two E. coli clones were grown and induced for 2 hours with IPTG, either at room temperature or at 37C. Full length SARS CoV-2 N is highly expressed expressed as a 50 kDa polypeptide in cultures induced at 37C (lanes 3, 5), but produced only trace amounts of protein at room temperature (lanes 2, 4). A 21 kDa NTD fragment was highly expressed and purified from cultures induced and grown at 37C (lanes 7, 9). Cultures induced at RT produced only trace amounts of protein (lanes 6, 8). SDS-PAGE molecular weight marker (lane 1) is shown for size estimation.