1QMN

Alpha1-antichymotrypsin serpin in the delta conformation (partial loop insertion)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.27 Å
  • R-Value Free: 0.243 
  • R-Value Work: 0.197 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Inactive Conformation of the Serpin Alpha1-Antichymotrypsin Indicates Two-Stage Insertion of the Reactive Loop: Implications for Inhibitory Function and Conformational Disease

Gooptu, B.Hazes, B.Chang, W.-S.W.Dafforn, T.R.Carrell, R.W.Read, R.J.Lomas, D.A.

(2000) Proc.Natl.Acad.Sci.USA 97: 67


  • PubMed Abstract: 
  • The serpins are a family of proteinase inhibitors that play a central role in the control of proteolytic cascades. Their inhibitory mechanism depends on the intramolecular insertion of the reactive loop into beta-sheet A after cleavage by the target ...

    The serpins are a family of proteinase inhibitors that play a central role in the control of proteolytic cascades. Their inhibitory mechanism depends on the intramolecular insertion of the reactive loop into beta-sheet A after cleavage by the target proteinase. Point mutations within the protein can allow aberrant conformational transitions characterized by beta-strand exchange between the reactive loop of one molecule and beta-sheet A of another. These loop-sheet polymers result in diseases as varied as cirrhosis, emphysema, angio-oedema, and thrombosis, and we recently have shown that they underlie an early-onset dementia. We report here the biochemical characteristics and crystal structure of a naturally occurring variant (Leu-55-Pro) of the plasma serpin alpha(1)-antichymotrypsin trapped as an inactive intermediate. The structure demonstrates a serpin configuration with partial insertion of the reactive loop into beta-sheet A. The lower part of the sheet is filled by the last turn of F-helix and the loop that links it to s3A. This conformation matches that of proposed intermediates on the pathway to complex and polymer formation in the serpins. In particular, this intermediate, along with the latent and polymerized conformations, explains the loss of activity of plasma alpha(1)-antichymotrypsin associated with chronic obstructive pulmonary disease in patients with the Leu-55-Pro mutation.


    Organizational Affiliation

    Respiratory Medicine Unit, Department of Medicine University of Cambridge, United Kingdom.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
ALPHA-1-ANTICHYMOTRYPSIN
A
401Homo sapiensGene Names: SERPINA3 (AACT)
Find proteins for P01011 (Homo sapiens)
Go to Gene View: SERPINA3
Go to UniProtKB:  P01011
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.27 Å
  • R-Value Free: 0.243 
  • R-Value Work: 0.197 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 41.723α = 90.00
b = 122.094β = 101.03
c = 41.724γ = 90.00
Software Package:
Software NamePurpose
AMoREphasing
CNSrefinement
SCALAdata scaling
MOSFLMdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2000-01-17
    Type: Initial release
  • Version 1.1: 2012-11-28
    Type: Database references, Derived calculations, Other, Refinement description, Structure summary, Version format compliance