Trinuclear copper biocatalytic center forms an active site of thiocyanate dehydrogenase

• DOI: 10.1073/pnas.1922133117
• Publication Date: 2020-02-25T01:26:11Z
• Authors: Tamara V. Tikhonova; Dimitry Y. Sorokin; Wilfred R. Hagen; Maria G. Khrenova; Gerard Muyzer; Tatiana V. Rakitina; Ivan G. Shabalin; Anton A. Trofimov; Stanislav I. Tsal...; Vladimir O. Popov
• Keywords: Thiocyanate; Cyanate; Active center

Biocatalytic copper centers are generally involved in the activation and reduction of dioxygen, with only few exceptions known. Here we report discovery characterization a previously undescribed center that forms active site copper-containing enzyme thiocyanate dehydrogenase (suggested EC 1.8.2.7) was purified from haloalkaliphilic sulfur-oxidizing bacterium genus Thioalkalivibrio ubiquitous saline alkaline soda lakes. The cluster is formed by three ions located at corners near-isosceles triangle facilitates direct conversion into cyanate, elemental sulfur, two reducing equivalents without involvement molecular oxygen. A mechanism catalysis suggested based on high-resolution three-dimensional structures, electron paramagnetic resonance (EPR) spectroscopy, quantum mechanics/molecular mechanics (QM/MM) simulations, kinetic studies, results site-directed mutagenesis.