Biophysical and structural characterization of the putative nickel chaperone CooT from Carboxydothermus hydrogenoformans

• Published in: Journal of biological inorganic chemistry 2018-07, Vol.23 (5), p.809-817
• Main Authors: Alfano, M., Pérard, J., Miras, R., Catty, P., Cavazza, C.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Anaerobic microorganisms; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - isolation & purification; Bacteriology; Binding sites; Biochemistry; Biochemistry, Molecular Biology; Biomedical and Life Sciences; Biophysical Phenomena; Biophysics; Carbon cycle; Crystallography, X-Ray; Enzymes; Histidine; Inorganic chemistry; Iron; Life Sciences; Microbiology; Microbiology and Parasitology; Molecular Chaperones - chemistry; Molecular Chaperones - genetics; Molecular Chaperones - isolation & purification; Mutagenesis, Site-Directed; Nickel; Nickel - chemistry; Original Paper; Protein Conformation; Sequence Homology, Amino Acid; Structural Biology; Thermoanaerobacterium - chemistry
• ISSN: 0949-8257; 1432-1327
• DOI: 10.1007/s00775-018-1576-2

Carboxydothermus hydrogenoformans is a model microorganism for the study of [NiFe]–CODH, a key enzyme of carbon cycle in anaerobic microorganisms. The enzyme possesses a unique active site (C-cluster), constituted of a distorted [NiFe 3 S 4 ] cubane linked to a mononuclear Fe(II) center. Both the biogenesis of the C-cluster and the activation of CODH by nickel insertion remain unclear. Among the three accessory proteins thought to play a role in this latter step (CooC, CooJ, and CooT), CooT is identified as a nickel chaperone involved in CODH maturation in Rhodospirillum rubrum . Here, we structurally and biophysically characterized a putative CooT protein present in C. hydrogenoformans (pChCooT). Despite the low sequence homologies between CooT from R. rubrum (RrCooT) and pChCooT (19% sequence identity), the two proteins share several similarities, such as their overall structure and a solvent-exposed Ni(II)-binding site at the dimer interface. Moreover, the X-ray structure of pChCooT reveals the proximity between the histidine 55, a potential nickel-coordinating residue, and the cysteine 2, a highly conserved key residue in Ni(II)-binding.