A study recently published in Hepatology Communications provided insights into a variant of MTARC1 protein, which conveys protection against liver disease. Here, we report a crystal structure of the variant protein at near‐atomic resolution and compare it to the structure of the wildtype protein.

Active site architecture reveals coordination sphere flexibility and specificity determinants in a group of closely related molybdoenzymes,

Human mitochondrial amidoxime reducing component 1 and 2 (mARC1 and mARC2) were immobilised on glassy carbon electrodes using the crosslinker glutaraldehyde. Voltammetry was performed in the presence of the artificial electron transfer mediator methyl viologen, whose redox potential lies negative of the enzymes' Mo VI/V and Mo V/IV redox potentials which were determined from optical spectroelectrochemical and EPR measurements. Apparent Michaelis constants obtained from catalytic limiting currents at various substrate concentrations were comparable to those previously reported in the literature from enzymatic assays. Kinetic parameters for benzamidoxime reduction were determined from cyclic voltammograms simulated using Digisim. pH dependence and stability of the enzyme electrode with time were also determined from limiting catalytic currents in saturating concentrations of benzamidoxime. The same electrode remained active after at least 9 days. Fabrication of this versatile and costeffective biosensor is effective in screening new pharmaceutically important substrates and mARC inhibitors.

Recent genome-wide association studies (GWAS) have shown a common variant of the mARC1 protein to be associated with liver disease. Herein, we present the crystal structure of this mARC1 p.Ala165Thr at near-atomic resolution. No relevant differences between the structure of wild type mARC1 and the variant protein are detected.