1ATU

UNCLEAVED ALPHA-1-ANTITRYPSIN


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.70 Å
  • R-Value Work: 0.195 
  • R-Value Observed: 0.195 

Starting Model: experimental
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This is version 1.5 of the entry. See complete history


Literature

The native strains in the hydrophobic core and flexible reactive loop of a serine protease inhibitor: crystal structure of an uncleaved alpha1-antitrypsin at 2.7 A.

Ryu, S.E.Choi, H.J.Kwon, K.S.Lee, K.N.Yu, M.H.

(1996) Structure 4: 1181-1192

  • DOI: https://doi.org/10.1016/s0969-2126(96)00126-8
  • Primary Citation of Related Structures:  
    1ATU

  • PubMed Abstract: 

    The protein alpha1-antitrypsin is a prototype member of the serpin (serine protease inhibitor) family and is known to inhibit the activity of neutrophil elastase in the lower respiratory tract. Members of this family undergo a large structural rearrangement upon binding to a target protease, involving cleavage of the reactive-site loop. This loop is then inserted into the main body of the enzyme following the opening of a central beta sheet, leading to stabilization of the structure. Random mutageneses of alpha1-antitrypsin identified various mutations that stabilize the native structure and retard the insertion of the reactive-site loop. Structural studies of these mutations may reveal the mechanism of the conformational change. We have determined the three-dimensional structure of an uncleaved alpha1-antitrypsin with seven such stabilizing mutations (hepta alpha1-antitrypsin) at 2.7 A resolution. From the comparison of the structure with other serpin structures, we found that hepta alpha1-antitrypsin is stabilized due to the release of various strains that exist in native wild type alpha1-antitrypsin, including unfavorable hydrophobic interactions in the central hydrophobic core. The reactive-site loop of hepta alpha1-antitrypsin is an extended strand, different from that of the previously determined structure of another uncleaved alpha1-antitrypsin, and indicates the inherent flexibility of the loop. The present structural study suggests that the uncleaved alpha1-antitrypsin has many folding defects which can be improved by mutations. These folding defects seem to be utilized in a coordinated fashion in the regulation of the conformational switch of alpha1-antitrypsin. Some of the defects, represented by the Phe51 region and possibly the Met374 and the Thr59 regions, are part of the sheet-opening mechanism.


  • Organizational Affiliation

    Protein Engineering Research Division, Korea Research Institute of Bioscience and Biotechnology, KIST, Yusong, Taejon, South Korea. ryuse@mcr1.geri.re.kr


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
ALPHA-1-ANTITRYPSIN374Homo sapiensMutation(s): 7 
UniProt & NIH Common Fund Data Resources
Find proteins for P01009 (Homo sapiens)
Explore P01009 
Go to UniProtKB:  P01009
PHAROS:  P01009
GTEx:  ENSG00000197249 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP01009
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.70 Å
  • R-Value Work: 0.195 
  • R-Value Observed: 0.195 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 115.78α = 90
b = 39.37β = 103.8
c = 90.43γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
RIGAKUdata reduction
RIGAKUdata scaling
X-PLORphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1997-08-20
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2021-11-03
    Changes: Database references, Other
  • Version 1.4: 2023-08-02
    Changes: Refinement description
  • Version 1.5: 2024-05-22
    Changes: Data collection