PDBsum entry 6hk5

Metal binding protein

PDB id: 6hk5

Contents

Protein chains

(+ 0 more) 66 a.a.

61 a.a.

Ligands

PEG ×4

PGE

Z3P

Metals

_CL ×3

_NI ×4

_CA

Waters ×300

PDB id:

6hk5

Name:

Metal binding protein

Title:

X-ray structure of a truncated mutant of the metallochaperone cooj with a high-affinity nickel-binding site

Structure:

Cooj. Chain: b, c, e, g, a, d, f, h. Fragment: residues 1-68. Engineered: yes

Source:

Rhodospirillum rubrum. Organism_taxid: 1085. Gene: cooj. Expressed in: escherichia coli 'bl21-gold(de3)plyss ag'. Expression_system_taxid: 866768.

Resolution:

2.04Å R-factor: 0.202 R-free: 0.259

Authors:

M.Alfano,J.Perard,C.Basset,P.Carpentier,B.Zambelli,J.Timm,S.Crouzy, S.Ciurli,C.Cavazza

Key ref:

M.Alfano et al. (2019). The carbon monoxide dehydrogenase accessory protein CooJ is a histidine-rich multidomain dimer containing an unexpected Ni(II)-binding site. J Biol Chem, 294, 7601-7614. PubMed id: 30858174 DOI: 10.1074/jbc.RA119.008011

Date:

05-Sep-18 Release date: 27-Mar-19

Protein chains

P72321  (P72321_RHORU) -  CooJ from Rhodospirillum rubrum

Seq: 115 a.a.

Struc: 66 a.a.

Protein chains

P72321  (P72321_RHORU) -  CooJ from Rhodospirillum rubrum

Seq: 115 a.a.

Struc: 61 a.a.

DOI no: 10.1074/jbc.RA119.008011

J Biol Chem 294:7601-7614 (2019)

PubMed id: 30858174

The carbon monoxide dehydrogenase accessory protein CooJ is a histidine-rich multidomain dimer containing an unexpected Ni(II)-binding site.

M.Alfano, J.Pérard, P.Carpentier, C.Basset, B.Zambelli, J.Timm, S.Crouzy, S.Ciurli, C.Cavazza.

ABSTRACT

Activation of nickel enzymes requires specific accessory proteins organized in multiprotein complexes controlling metal transfer to the active site. Histidine-rich clusters are generally present in at least one of the metallochaperones involved in nickel delivery. The maturation of carbon monoxide dehydrogenase in the proteobacterium Rhodospirillum rubrum requires three accessory proteins, CooC, CooT, and CooJ, dedicated to nickel insertion into the active site, a distorted [NiFe₃S₄] cluster coordinated to an iron site. Previously, CooJ from R. rubrum (RrCooJ) has been described as a nickel chaperone with 16 histidines and 2 cysteines at its C terminus. Here, the X-ray structure of a truncated version of RrCooJ, combined with small-angle X-ray scattering data and a modeling study of the full-length protein, revealed a homodimer comprising a coiled coil with two independent and highly flexible His tails. Using isothermal calorimetry, we characterized several metal-binding sites (four per dimer) involving the His-rich motifs and having similar metal affinity (K_D = 1.6 μm). Remarkably, biophysical approaches, site-directed mutagenesis, and X-ray crystallography uncovered an additional nickel-binding site at the dimer interface, which binds Ni(II) with an affinity of 380 nm Although RrCooJ was initially thought to be a unique protein, a proteome database search identified at least 46 bacterial CooJ homologs. These homologs all possess two spatially separated nickel-binding motifs: a variable C-terminal histidine tail and a strictly conserved H(W/F)X₂HX₃H motif, identified in this study, suggesting a dual function for CooJ both as a nickel chaperone and as a nickel storage protein.