1QFD

NMR SOLUTION STRUCTURE OF ALPHA-AMYLASE INHIBITOR (AAI)


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 50 
  • Conformers Submitted: 10 
  • Selection Criteria: LEAST RESTRAINT VIOLATION AND RESULT OF PROCHECK 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Solution structure of the major alpha-amylase inhibitor of the crop plant amaranth.

Lu, S.Deng, P.Liu, X.Luo, J.Han, R.Gu, X.Liang, S.Wang, X.Li, F.Lozanov, V.Patthy, A.Pongor, S.

(1999) J Biol Chem 274: 20473-20478

  • DOI: 10.1074/jbc.274.29.20473
  • Primary Citation of Related Structures:  
    1QFD

  • PubMed Abstract: 
  • alpha-Amylase inhibitor (AAI), a 32-residue miniprotein from the Mexican crop plant amaranth (Amaranthus hypochondriacus), is the smallest known alpha-amylase inhibitor and is specific for insect alpha-amylases (Chagolla-Lopez, A., Blanco-Labra, A., Patthy, A ...

    alpha-Amylase inhibitor (AAI), a 32-residue miniprotein from the Mexican crop plant amaranth (Amaranthus hypochondriacus), is the smallest known alpha-amylase inhibitor and is specific for insect alpha-amylases (Chagolla-Lopez, A., Blanco-Labra, A., Patthy, A., Sanchez, R., and Pongor, S. (1994) J. Biol. Chem. 269, 23675-23680). Its disulfide topology was confirmed by Edman degradation, and its three-dimensional solution structure was determined by two-dimensional 1H NMR spectroscopy at 500 MHz. Structural constraints (consisting of 348 nuclear Overhauser effect interproton distances, 8 backbone dihedral constraints, and 9 disulfide distance constraints) were used as an input to the X-PLOR program for simulated annealing and energy minimization calculations. The final set of 10 structures had a mean pairwise root mean square deviation of 0.32 A for the backbone atoms and 1.04 A for all heavy atoms. The structure of AAI consists of a short triple-stranded beta-sheet stabilized by three disulfide bonds, forming a typical knottin or inhibitor cystine knot fold found in miniproteins, which binds various macromolecular ligands. When the first intercystine segment of AAI (sequence IPKWNR) was inserted into a homologous position of the spider toxin Huwentoxin I, the resulting chimera showed a significant inhibitory activity, suggesting that this segment takes part in enzyme binding.


    Related Citations: 
    • Synthesis and Cystine/Cysteine-Catalyzed Oxidative Folding of the Amaranth Alpha-Amylase Inhibitor
      Lozanov, V., Guarnaccia, C., Patthy, A., Foti, S., Pongor, S.
      (1997) J Pept Res 50(1: 65
    • A Novel Alpha-Amylase Inhibitor from Amaranth (Amaranthus Hypocondriacus)Seeds
      Chagolla-Lopez, A., Blanco-Labra, A., Patthy, A., Sanchez, R., Pongor, S.
      (1994) J Biol Chem 269: 23675

    Organizational Affiliation

    Peking University, Beijing 100871, China.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
PROTEIN (ALPHA-AMYLASE INHIBITOR)A32Amaranthus hypochondriacusMutation(s): 0 
Gene Names: AAI
UniProt
Find proteins for P80403 (Amaranthus hypochondriacus)
Explore P80403 
Go to UniProtKB:  P80403
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP80403
Protein Feature View
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 50 
  • Conformers Submitted: 10 
  • Selection Criteria: LEAST RESTRAINT VIOLATION AND RESULT OF PROCHECK 
  • OLDERADO: 1QFD Olderado

Structure Validation

View Full Validation Report




Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1999-07-16
    Type: Initial release
  • Version 1.1: 2007-10-21
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-11-29
    Changes: Derived calculations