Abstract
Human coronavirus NL63 mainly infects younger children and causes cough, fever, rhinorrhoea, bronchiolitis and croup. It encodes two polyprotein precursors required for genome replication and transcription. Each polyprotein undergoes extensive proteolytic processing, resulting in functional subunits. This process is mainly mediated by its genome-encoded main protease, which is an attractive target for antiviral drug design. In this study, the main protease of human coronavirus NL63 was crystallized in complex with a Michael acceptor. The complex crystals diffracted to 2.85 Å resolution and belonged to space group P41212, with unit-cell parameters a = b = 87.2, c = 212.1 Å. Two molecules were identified per asymmetric unit.