PDBsum entry 4i8c

Transport protein

PDB id: 4i8c

Contents

Protein chains

499 a.a.

Ligands

HIS ×6

ACT ×16

GOL ×8

SO4 ×2

Metals

_NI ×3

_CL

Waters ×329

PDB id:

4i8c

Name:

Transport protein

Title:

X-ray structure of nika in complex with ni-(l-his)2

Structure:

Nickel-binding periplasmic protein. Chain: a, b, c. Engineered: yes

Source:

Escherichia coli. Organism_taxid: 83333. Strain: k12. Gene: nika, b3476, jw3441. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

2.50Å R-factor: 0.191 R-free: 0.234

Authors:

H.Lebrette,M.Iannello,J.C.Fontecilla-Camps,C.Cavazza

Key ref:

H.Lebrette et al. (2013). The binding mode of Ni-(L-His)2 in NikA revealed by X-ray crystallography. J Inorg Biochem, 121, 16-18. PubMed id: 23314594 DOI: 10.1016/j.jinorgbio.2012.12.010

Date:

03-Dec-12 Release date: 30-Jan-13

Protein chains

P33590  (NIKA_ECOLI) -  Nickel-binding periplasmic protein from Escherichia coli (strain K12)

Seq: 524 a.a.

Struc: 499 a.a.

DOI no: 10.1016/j.jinorgbio.2012.12.010

J Inorg Biochem 121:16-18 (2013)

PubMed id: 23314594

The binding mode of Ni-(L-His)2 in NikA revealed by X-ray crystallography.

H.Lebrette, M.Iannello, J.C.Fontecilla-Camps, C.Cavazza.

ABSTRACT

The ABC-type importer NikABCDE mediates nickel acquisition in Escherichia coli. The periplasmic nickel-binding component NikA has a folding similar to that of the peptide transporter OppA and does not bind free nickel. Instead, we showed that the metal is tetra-coordinated by an organic tri-dentate molecule and His416. Conversely, it has been recently reported that NikA binds Ni-((L)-His)(2) and that addition of histidine increases the rate of nickel uptake in vivo. Here, we report the structure of NikA/Ni-((L)-His)(2) and show that histidine binding differs from peptide binding in OppA. The structure also confirms the central role of His416 in nickel binding.