The QueF monomer is made up of two ferredoxin-like domains aligned together with their beta-sheets that have additional embellishments. This subunit is composed of a three-stranded beta-sheet and two alpha-helices. QueF reduces a nitrile bond to a primary amine. The two monomer units together create suitable substrate-binding pockets [1].

1: High-resolution structure of the nitrile reductase QueF combined with molecular simulations provide insight into enzyme mechanism. Kim Y, Zhou M, Moy S, Morales J, Cunningham MA, Joachimiak A; J Mol Biol. 2010;404:127-137. PMID:20875425