The complete structure of CorA magnesium transporter from Methanocaldococcus jannaschii

Experimental Data Snapshot

  • Resolution: 3.20 Å
  • R-Value Free: 0.282 
  • R-Value Work: 0.205 
  • R-Value Observed: 0.209 

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Structural insights into the mechanisms of Mg2+ uptake, transport, and gating by CorA

Guskov, A.Nordin, N.Reynaud, A.Engman, H.Lundback, A.K.Jong, A.J.Cornvik, T.Phua, T.Eshaghi, S.

(2012) Proc Natl Acad Sci U S A 109: 18459-18464

  • DOI: https://doi.org/10.1073/pnas.1210076109
  • Primary Citation of Related Structures:  
    4EGW, 4EV6

  • PubMed Abstract: 

    Despite the importance of Mg(2+) for numerous cellular activities, the mechanisms underlying its import and homeostasis are poorly understood. The CorA family is ubiquitous and is primarily responsible for Mg(2+) transport. However, the key questions-such as, the ion selectivity, the transport pathway, and the gating mechanism-have remained unanswered for this protein family. We present a 3.2 Å resolution structure of the archaeal CorA from Methanocaldococcus jannaschii, which is a unique complete structure of a CorA protein and reveals the organization of the selectivity filter, which is composed of the signature motif of this family. The structure reveals that polar residues facing the channel coordinate a partially hydrated Mg(2+) during the transport. Based on these findings, we propose a unique gating mechanism involving a helical turn upon the binding of Mg(2+) to the regulatory intracellular binding sites, and thus converting a polar ion passage into a narrow hydrophobic pore. Because the amino acids involved in the uptake, transport, and gating are all conserved within the entire CorA family, we believe this mechanism is general for the whole family including the eukaryotic homologs.

  • Organizational Affiliation

    Division of Structural Biology and Biochemistry, School of Biological Sciences, Nanyang Technological University, Singapore 637551, Republic of Singapore.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Magnesium transport protein CorA
A, B, C, D, E
339Methanocaldococcus jannaschii DSM 2661Mutation(s): 0 
Gene Names: corAMJ1033
Membrane Entity: Yes 
Find proteins for Q58439 (Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440))
Explore Q58439 
Go to UniProtKB:  Q58439
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ58439
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on UMQ

Download Ideal Coordinates CCD File 
F [auth A]
G [auth A]
IA [auth E]
JA [auth E]
O [auth B]
F [auth A],
G [auth A],
IA [auth E],
JA [auth E],
O [auth B],
P [auth B],
T [auth C],
X [auth D]
C23 H44 O11
Query on MG

Download Ideal Coordinates CCD File 
AA [auth D]
BA [auth D]
CA [auth D]
DA [auth D]
EA [auth D]
AA [auth D],
BA [auth D],
CA [auth D],
DA [auth D],
EA [auth D],
FA [auth D],
GA [auth D],
H [auth A],
HA [auth D],
I [auth A],
J [auth A],
K [auth A],
KA [auth E],
L [auth A],
LA [auth E],
M [auth A],
MA [auth E],
N [auth A],
NA [auth E],
OA [auth E],
PA [auth E],
Q [auth B],
QA [auth E],
R [auth B],
RA [auth E],
S [auth B],
SA [auth E],
U [auth C],
V [auth C],
W [auth C],
Y [auth D],
Z [auth D]
Experimental Data & Validation

Experimental Data

  • Resolution: 3.20 Å
  • R-Value Free: 0.282 
  • R-Value Work: 0.205 
  • R-Value Observed: 0.209 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 103.11α = 90
b = 124.83β = 90.76
c = 111.88γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
XDSdata reduction
XDSdata scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-10-31
    Type: Initial release
  • Version 1.1: 2013-07-24
    Changes: Database references
  • Version 1.2: 2023-11-08
    Changes: Data collection, Database references, Derived calculations, Refinement description