Electrochemical behaviour of bacterial nitric oxide reductase-Evidence of low redox potential non-heme FeB gives new perspectives on the catalytic mechanism

► This work reports the cNOR characterization attained via direct electron transfer. ► Metal centre midpoint potentials and number of involved electrons were estimated. ► Redox centres' pH dependence was evaluated. ► Non-heme iron FeB process occurs at lower potential value than previously reported. ► Electrochemical results of heme b3 on turnover conditions point to cis-FeB mechanism.