The two CO-dehydrogenases of Thermococcus sp. AM4

• Published in: Biochimica et biophysica acta. Bioenergetics 2020-07, Vol.1861 (7), p.148188-148188, Article 148188
• Main Authors: Benvenuti, Martino, Meneghello, Marta, Guendon, Chloé, Jacq-Bailly, Aurore, Jeoung, Jae-Hun, Dobbek, Holger, Léger, Christophe, Fourmond, Vincent, Dementin, Sébastien
• Format: Article
• Language: English
• Subjects: Biochemistry, Molecular Biology; Chemical Sciences; Crystal structure; Life Sciences; Metalloenzyme; Metalloenzyme maturation; Ni-containing carbon monoxide dehydrogenase; Protein film voltammetry
• ISSN: 0005-2728; 1879-2650
• DOI: 10.1016/j.bbabio.2020.148188

Ni-containing CO-dehydrogenases (CODHs) allow some microorganisms to couple ATP synthesis to CO oxidation, or to use either CO or CO2 as a source of carbon. The recent detailed characterizations of some of them have evidenced a great diversity in terms of catalytic properties and resistance to O2. In an effort to increase the number of available CODHs, we have heterologously produced in Desulfovibrio fructosovorans, purified and characterized the two CooS-type CODHs (CooS1 and CooS2) from the hyperthermophilic archaeon Thermococcus sp. AM4 (Tc). We have also crystallized CooS2, which is coupled in vivo to a hydrogenase. CooS1 and CooS2 are homodimers, and harbour five metalloclusters: two [Ni4Fe-4S] C clusters, two [4Fe-4S] B clusters and one interfacial [4Fe-4S] D cluster. We show that both are dependent on a maturase, CooC1 or CooC2, which is interchangeable. The homologous protein CooC3 does not allow Ni insertion in either CooS. The two CODHs from Tc have similar properties: they can both oxidize and produce CO. The Michaelis constants (Km) are in the microM range for CO and in the mM range (CODH 1) or above (CODH 2) for CO2. Product inhibition is observed only for CO2 reduction, consistent with CO2 binding being much weaker than CO binding. The two enzymes are rather O2 sensitive (similarly to CODH II from Carboxydothermus hydrogenoformans), and react more slowly with O2 than any other CODH for which these data are available. •Thermococcus sp. AM4's genome contains 2 functional CODHs.•Their correct maturation is dependent on CooC maturation factors.•They can both oxidize CO and reduce CO2, with mM for CO2.•CO2 reduction is inhibited by CO, but CO oxidation is not inhibited by CO2.•Both CODHs react much more slowly with O2 than all other CODHs.