1.12 Å resolution crystal structure of the catalytic domain of the plasmid-mediated colistin resistance determinant MCR-2

MCR-2 confers resistance to colistin, a ‘last-line’ antibiotic against extensively-resistant Gram-negative pathogens. It is a plasmid-encoded phosphoethanolamine transferase closely related to MCR 1. To understand the diversity in the MCR-family we have determined the 1.12 Å resolution crystal structure of the MCR-2 catalytic domain. Variable amino acids are located distant from both the di-zinc active site and membrane-proximal face. The exceptionally high resolution will provide an accurate starting model for further mechanistic studies.