Experimental Data Snapshot

  • Resolution: 2.00 Å
  • R-Value Free: 0.204 
  • R-Value Work: 0.157 
  • R-Value Observed: 0.157 

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Crystal structures of the psychrophilic alpha-amylase from Alteromonas haloplanctis in its native form and complexed with an inhibitor.

Aghajari, N.Feller, G.Gerday, C.Haser, R.

(1998) Protein Sci 7: 564-572

  • DOI: https://doi.org/10.1002/pro.5560070304
  • Primary Citation of Related Structures:  
    1AQH, 1AQM

  • PubMed Abstract: 

    Alteromonas haloplanctis is a bacterium that flourishes in Antarctic sea-water and it is considered as an extreme psychrophile. We have determined the crystal structures of the alpha-amylase (AHA) secreted by this bacterium, in its native state to 2.0 angstroms resolution as well as in complex with Tris to 1.85 angstroms resolution. The structure of AHA, which is the first experimentally determined three-dimensional structure of a psychrophilic enzyme, resembles those of other known alpha-amylases of various origins with a surprisingly greatest similarity to mammalian alpha-amylases. AHA contains a chloride ion which activates the hydrolytic cleavage of substrate alpha-1,4-glycosidic bonds. The chloride binding site is situated approximately 5 angstroms from the active site which is characterized by a triad of acid residues (Asp 174, Glu 200, Asp 264). These are all involved in firm binding of the Tris moiety. A reaction mechanism for substrate hydrolysis is proposed on the basis of the Tris inhibitor binding and the chloride activation. A trio of residues (Ser 303, His 337, Glu 19) having a striking spatial resemblance with serine-protease like catalytic triads was found approximately 22 angstroms from the active site. We found that this triad is equally present in other chloride dependent alpha-amylases, and suggest that it could be responsible for autoproteolytic events observed in solution for this cold adapted alpha-amylase.

  • Organizational Affiliation

    Laboratoire d'Architecture et Fonction des Macromolécules Biologiques, UPR9039, Institut de Biologie Structurale et Microbiologie, IFR1, CNRS, Marseille, France.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
ALPHA-AMYLASE453Pseudoalteromonas haloplanktisMutation(s): 0 
Gene Names: AMY
Find proteins for P29957 (Pseudoalteromonas haloplanktis)
Explore P29957 
Go to UniProtKB:  P29957
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP29957
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.00 Å
  • R-Value Free: 0.204 
  • R-Value Work: 0.157 
  • R-Value Observed: 0.157 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 71.4α = 90
b = 138.7β = 90
c = 115.7γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
AGROVATAdata reduction
X-PLORmodel building
AGROVATAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1999-02-16
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance