Histidine 416 of the periplasmic binding protein NikA is essential for nickel uptake in Escherichia coli

Christine Cavazza (1) , Lydie Martin (1) , Emmanuelle Laffly (1) , Hugo Lebrette (1) , Mickael V Cherrier (1) , Laura Zeppieri (1) , Pierre Richaud (2, 3) , Marie Carrière (4) , Juan-Carlos Fontecilla-Camps (1)

1 IBS - UMR 5075 - Institut de biologie structurale
2 BCMPB - Biologie cellulaire et moléculaire des plantes et des bactéries
3 BIAM - Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB)
4 SIS2M UMR 3299 - Service Interdisciplinaire sur les Systèmes Moléculaires et les Matériaux (ex SCM)

Escherichia coli require nickel for the synthesis of [NiFe] hydrogenases under anaerobic growth conditions. Nickel import depends on the specific ABC‐transporter NikABCDE encoded by the nik operon, which deletion causes the complete abolition of hydrogenase activity. We have previously postulated that the periplasmic binding protein NikA binds a natural metallophore containing three carboxylate functions that coordinate a Ni(II) ion, the fourth ligand being His416, the only direct metal‐protein contact, completing a square‐planar coordination for the metal. The crystal structure of the H416I mutant showed no electron density corresponding to a metal‐chelator complex. In vivo experiments indicate that the mutation causes a significant decrease in nickel uptake and hydrogenase activity. These results confirm the essential role of His416 in nickel transport by NikA.

Domaines: Sciences du Vivant [q-bio]

Christine Cavazza, Lydie Martin, Emmanuelle Laffly, Hugo Lebrette, Mickael V Cherrier, et al.. Histidine 416 of the periplasmic binding protein NikA is essential for nickel uptake in Escherichia coli. FEBS Letters, 2011, 585 (4), pp.711 - 715. ⟨10.1016/j.febslet.2011.01.038⟩. ⟨hal-01930673⟩