2QM8

MeaB, A Bacterial Homolog of MMAA, in the Nucleotide Free Form


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.7 Å
  • R-Value Free: 0.208 
  • R-Value Work: 0.175 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Crystal structure and mutagenesis of the metallochaperone MeaB: insight into the causes of methylmalonic aciduria.

Hubbard, P.A.Padovani, D.Labunska, T.Mahlstedt, S.A.Banerjee, R.Drennan, C.L.

(2007) J.Biol.Chem. 282: 31308-31316

  • DOI: 10.1074/jbc.M704850200
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • MeaB is an auxiliary protein that plays a crucial role in the protection and assembly of the B(12)-dependent enzyme methylmalonyl-CoA mutase. Impairments in the human homologue of MeaB, MMAA, lead to methylmalonic aciduria, an inborn error of metabol ...

    MeaB is an auxiliary protein that plays a crucial role in the protection and assembly of the B(12)-dependent enzyme methylmalonyl-CoA mutase. Impairments in the human homologue of MeaB, MMAA, lead to methylmalonic aciduria, an inborn error of metabolism. To explore the role of this metallochaperone, its structure was solved in the nucleotide-free form, as well as in the presence of product, GDP. MeaB is a homodimer, with each subunit containing a central alpha/beta-core G domain that is typical of the GTPase family, as well as alpha-helical extensions at the N and C termini that are not found in other metalloenzyme chaperone GTPases. The C-terminal extension appears to be essential for nucleotide-independent dimerization, and the N-terminal region is implicated in protein-protein interaction with its partner protein, methylmalonyl-CoA mutase. The structure of MeaB confirms that it is a member of the G3E family of P-loop GTPases, which contains other putative metallochaperones HypB, CooC, and UreG. Interestingly, the so-called switch regions, responsible for signal transduction following GTP hydrolysis, are found at the dimer interface of MeaB instead of being positioned at the surface of the protein where its partner protein methylmalonyl-CoA mutase should bind. This observation suggests a large conformation change of MeaB must occur between the GDP- and GTP-bound forms of this protein. Because of their high sequence homology, the missense mutations in MMAA that result in methylmalonic aciduria have been mapped onto MeaB and, in conjunction with mutagenesis data, provide possible explanations for the pathology of this disease.


    Organizational Affiliation

    Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
GTPase/ATPase
A, B
337Methylobacterium extorquensMutation(s): 3 
Gene Names: meaB
Find proteins for Q8RPA0 (Methylobacterium extorquens)
Go to UniProtKB:  Q8RPA0
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
PO4
Query on PO4

Download SDF File 
Download CCD File 
A, B
PHOSPHATE ION
O4 P
NBIIXXVUZAFLBC-UHFFFAOYSA-K
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MSE
Query on MSE
A, B
L-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.7 Å
  • R-Value Free: 0.208 
  • R-Value Work: 0.175 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 59.410α = 90.00
b = 77.040β = 95.55
c = 79.950γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data reduction
ADSCdata collection
HKL-2000data scaling
PHASERphasing
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-08-28
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Source and taxonomy, Version format compliance