Comment on "Structural evidence for a dynamic metallocofactor during N(2) reduction by Mo-nitrogenase"

Kang et al (Reports, 19 June 2020, p. 1381) report a structure of the nitrogenase MoFe protein that is interpreted to indicate binding of N(2) or an N(2)-derived species to the active-site FeMo cofactor. Independent refinement of the structure and consideration of biochemical evidence do not support this claim.