Premium
Histidine 416 of the periplasmic binding protein NikA is essential for nickel uptake in Escherichia coli
Author(s) -
Cavazza Christine,
Martin Lydie,
Laffly Emmanuelle,
Lebrette Hugo,
Cherrier Mickaël V.,
Zeppieri Laura,
Richaud Pierre,
Carrière Marie,
Fontecilla-Camps Juan C.
Publication year - 2011
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2011.01.038
Subject(s) - periplasmic space , operon , hydrogenase , nickel , escherichia coli , chemistry , histidine , metal , ligand (biochemistry) , biochemistry , crystallography , stereochemistry , enzyme , gene , organic chemistry , receptor
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.