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: 2.3 Å
  • R-Value Free: 0.281 
  • R-Value Work: 0.244 

wwPDB Validation 3D Report Full Report


This is version 1.1 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: 10.1042/BJ20070764

  • 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 locati ...

    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: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Alpha-2-macroglobulin
A, B
102Homo sapiensGene Names: A2M (CPAMD5)
Find proteins for P01023 (Homo sapiens)
Go to Gene View: A2M
Go to UniProtKB:  P01023
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.3 Å
  • R-Value Free: 0.281 
  • R-Value Work: 0.244 
  • Space Group: P 43 21 2
Unit Cell:
Length (Å)Angle (°)
a = 68.810α = 90.00
b = 68.810β = 90.00
c = 120.070γ = 90.00
Software Package:
Software NamePurpose
SOLVEphasing
HKL-2000data scaling
CNSrefinement
HKL-2000data collection
HKL-2000data reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2007-03-26 
  • Released Date: 2007-08-21 
  • Deposition Author(s): Doan, N.

Revision History 

  • Version 1.0: 2007-08-21
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance