Structure of KHK in complex with compound 4 (6-[(1~{S},5~{R})-6-(hydroxymethyl)-3-azabicyclo[3.1.0]hexan-3-yl]-2-[(2~{S},3~{R})-2-methyl-3-oxidanyl-azetidin-1-yl]-4-(trifluoromethyl)pyridine-3-carbonitrile)