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Crystal Structure of Methylmalonic Acidemia Type A Protein


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.64 Å
  • R-Value Free: 0.222 
  • R-Value Work: 0.182 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Structures of the Human Gtpase Mmaa and Vitamin B12-Dependent Methylmalonyl-Coa Mutase and Insight Into Their Complex Formation.

Froese, D.S.Kochan, G.Muniz, J.R.C.Wu, X.Gileadi, C.Ugochukwu, E.Krysztofinska, E.Gravel, R.A.Oppermann, U.Yue, W.W.

(2010) J.Biol.Chem. 285: 38204

  • DOI: 10.1074/jbc.M110.177717
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Vitamin B(12) (cobalamin, Cbl) is essential to the function of two human enzymes, methionine synthase (MS) and methylmalonyl-CoA mutase (MUT). The conversion of dietary Cbl to its cofactor forms, methyl-Cbl (MeCbl) for MS and adenosyl-Cbl (AdoCbl) fo ...

    Vitamin B(12) (cobalamin, Cbl) is essential to the function of two human enzymes, methionine synthase (MS) and methylmalonyl-CoA mutase (MUT). The conversion of dietary Cbl to its cofactor forms, methyl-Cbl (MeCbl) for MS and adenosyl-Cbl (AdoCbl) for MUT, located in the cytosol and mitochondria, respectively, requires a complex pathway of intracellular processing and trafficking. One of the processing proteins, MMAA (methylmalonic aciduria type A), is implicated in the mitochondrial assembly of AdoCbl into MUT and is defective in children from the cblA complementation group of cobalamin disorders. To characterize the functional interplay between MMAA and MUT, we have crystallized human MMAA in the GDP-bound form and human MUT in the apo, holo, and substrate-bound ternary forms. Structures of both proteins reveal highly conserved domain architecture and catalytic machinery for ligand binding, yet they show substantially different dimeric assembly and interaction, compared with their bacterial counterparts. We show that MMAA exhibits GTPase activity that is modulated by MUT and that the two proteins interact in vitro and in vivo. Formation of a stable MMAA-MUT complex is nucleotide-selective for MMAA (GMPPNP over GDP) and apoenzyme-dependent for MUT. The physiological importance of this interaction is highlighted by a recently identified homoallelic patient mutation of MMAA, G188R, which, we show, retains basal GTPase activity but has abrogated interaction. Together, our data point to a gatekeeping role for MMAA by favoring complex formation with MUT apoenzyme for AdoCbl assembly and releasing the AdoCbl-loaded holoenzyme from the complex, in a GTP-dependent manner.


    Organizational Affiliation

    Structural Genomics Consortium, University of Oxford OX3 7DU, United Kingdom.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
METHYLMALONIC ACIDURIA TYPE A PROTEIN, MITOCHONDRIAL
A, B, C, D
349Homo sapiensMutation(s): 0 
Gene Names: MMAA
EC: 3.6.-.-
Find proteins for Q8IVH4 (Homo sapiens)
Go to Gene View: MMAA
Go to UniProtKB:  Q8IVH4
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GDP
Query on GDP

Download SDF File 
Download CCD File 
A, B, C, D
GUANOSINE-5'-DIPHOSPHATE
C10 H15 N5 O11 P2
QGWNDRXFNXRZMB-UUOKFMHZSA-N
 Ligand Interaction
2PE
Query on 2PE

Download SDF File 
Download CCD File 
A, C, D
NONAETHYLENE GLYCOL
C18 H38 O10
YZUUTMGDONTGTN-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.64 Å
  • R-Value Free: 0.222 
  • R-Value Work: 0.182 
  • Space Group: P 42
Unit Cell:
Length (Å)Angle (°)
a = 149.430α = 90.00
b = 149.430β = 90.00
c = 69.060γ = 90.00
Software Package:
Software NamePurpose
PHASERphasing
iMOSFLMdata reduction
SCALAdata scaling
BUSTERrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Revision History 

  • Version 1.0: 2009-11-17
    Type: Initial release
  • Version 1.1: 2013-11-27
    Type: Source and taxonomy, Version format compliance