2P9R

Human alpha2-macroglogulin is composed of multiple domains, as predicted by homology with complement component C3


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.281 
  • R-Value Work: 0.244 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Human alpha2-macroglobulin is composed of multiple domains, as predicted by homology with complement component C3.

Doan, N.Gettins, P.G.

(2007) Biochem J 407: 23-30

  • DOI: https://doi.org/10.1042/BJ20070764
  • Primary Citation of Related Structures:  
    2P9R

  • PubMed Abstract: 

    Human alpha2M (alpha2-macroglobulin) and the complement components C3 and C4 are thiol ester-containing proteins that evolved from the same ancestral gene. The recent structure determination of human C3 has allowed a detailed prediction of the location of domains within human alpha2M to be made. We describe here the expression and characterization of three alpha(2)M domains predicted to be involved in the stabilization of the thiol ester in native alpha2M and in its activation upon bait region proteolysis. The three newly expressed domains are MG2 (macroglobulin domain 2), TED (thiol ester-containing domain) and CUB (complement protein subcomponents C1r/C1s, urchin embryonic growth factor and bone morphogenetic protein 1) domain. Together with the previously characterized RBD (receptor-binding domain), they represent approx. 42% of the alpha2M polypeptide. Their expression as folded domains strongly supports the predicted domain organization of alpha2M. An X-ray crystal structure of MG2 shows it to have a fibronectin type-3 fold analogous to MG1-MG8 of C3. TED is, as predicted, an alpha-helical domain. CUB is a spliced domain composed of two stretches of polypeptide that flank TED in the primary structure. In intact C3 TED interacts with RBD, where it is in direct contact with the thiol ester, and with MG2 and CUB on opposite, flanking sides. In contrast, these alpha2M domains, as isolated species, show negligible interaction with one another, suggesting that the native conformation of alpha2M, and the consequent thiol ester-stabilizing domain-domain interactions, result from additional restraints imposed by the physical linkage of these domains or by additional domains in the protein.


  • Organizational Affiliation

    Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607, U.S.A.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Alpha-2-macroglobulin
A, B
102Homo sapiensMutation(s): 0 
Gene Names: A2M
UniProt & NIH Common Fund Data Resources
Find proteins for P01023 (Homo sapiens)
Explore P01023 
Go to UniProtKB:  P01023
PHAROS:  P01023
GTEx:  ENSG00000175899 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP01023
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.281 
  • R-Value Work: 0.244 
  • Space Group: P 43 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 68.81α = 90
b = 68.81β = 90
c = 120.07γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
SOLVEphasing
CNSrefinement
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

  • Released Date: 2007-08-21 
  • Deposition Author(s): Doan, N.

Revision History  (Full details and data files)

  • Version 1.0: 2007-08-21
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2024-02-21
    Changes: Data collection, Database references