1RP8

Crystal structure of barley alpha-amylase isozyme 1 (amy1) inactive mutant d180a in complex with maltoheptaose


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.00 Å
  • R-Value Free: 0.221 
  • R-Value Work: 0.172 
  • R-Value Observed: 0.172 

wwPDB Validation   3D Report Full Report


This is version 2.0 of the entry. See complete history


Literature

Oligosaccharide Binding to Barley {alpha}-Amylase 1

Robert, X.Haser, R.Mori, H.Svensson, B.Aghajari, N.

(2005) J Biol Chem 280: 32968-32978

  • DOI: 10.1074/jbc.M505515200
  • Primary Citation of Related Structures:  
    1RPK, 1RP9, 1RP8

  • PubMed Abstract: 
  • Enzymatic subsite mapping earlier predicted 10 binding subsites in the active site substrate binding cleft of barley alpha-amylase isozymes. The three-dimensional structures of the oligosaccharide complexes with barley alpha-amylase isozyme 1 (AMY1) described here give for the first time a thorough insight into the substrate binding by describing residues defining 9 subsites, namely -7 through +2 ...

    Enzymatic subsite mapping earlier predicted 10 binding subsites in the active site substrate binding cleft of barley alpha-amylase isozymes. The three-dimensional structures of the oligosaccharide complexes with barley alpha-amylase isozyme 1 (AMY1) described here give for the first time a thorough insight into the substrate binding by describing residues defining 9 subsites, namely -7 through +2. These structures support that the pseudotetrasaccharide inhibitor acarbose is hydrolyzed by the active enzymes. Moreover, sugar binding was observed to the starch granule-binding site previously determined in barley alpha-amylase isozyme 2 (AMY2), and the sugar binding modes are compared between the two isozymes. The "sugar tongs" surface binding site discovered in the AMY1-thio-DP4 complex is confirmed in the present work. A site that putatively serves as an entrance for the substrate to the active site was proposed at the glycone part of the binding cleft, and the crystal structures of the catalytic nucleophile mutant (AMY1D180A) complexed with acarbose and maltoheptaose, respectively, suggest an additional role for the nucleophile in the stabilization of the Michaelis complex. Furthermore, probable roles are outlined for the surface binding sites. Our data support a model in which the two surface sites in AMY1 can interact with amylose chains in their naturally folded form. Because of the specificities of these two sites, they may locate/orient the enzyme in order to facilitate access to the active site for polysaccharide chains. Moreover, the sugar tongs surface site could also perform the unraveling of amylose chains, with the aid of Tyr-380 acting as "molecular tweezers."


    Organizational Affiliation

    Laboratoire de BioCristallographie, IFR-128 BioSciences Lyon-Gerland, Institut de Biologie et Chimie des Protéines, UMR 5086, CNRS-UCBL1, 7 Passage du Vercors, F-69367 Lyon Cedex 07, France.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Alpha-amylase type 1 isozymeA405Hordeum vulgareMutation(s): 1 
Gene Names: AMY1.1
EC: 3.2.1.1
UniProt
Find proteins for P00693 (Hordeum vulgare)
Explore P00693 
Go to UniProtKB:  P00693
Protein Feature View
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  • Reference Sequence
Oligosaccharides

Help

Entity ID: 2
MoleculeChainsChain Length2D DiagramGlycosylation3D Interactions
alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-beta-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranoseB7N/A Oligosaccharides Interaction
Glycosylation Resources
GlyTouCan:  G19668TL
GlyCosmos:  G19668TL
GlyGen:  G19668TL
Entity ID: 3
MoleculeChainsChain Length2D DiagramGlycosylation3D Interactions
alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranoseC, D5N/A Oligosaccharides Interaction
Glycosylation Resources
GlyTouCan:  G50146AM
GlyCosmos:  G50146AM
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download Ideal Coordinates CCD File 
E [auth A], F [auth A], G [auth A]CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Biologically Interesting Molecules (External Reference) 1 Unique
Entity ID: 3
IDChainsNameType/Class2D Diagram3D Interactions
PRD_900030
Query on PRD_900030
C, Dalpha-maltopentaoseOligosaccharide /  Substrate analog Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.00 Å
  • R-Value Free: 0.221 
  • R-Value Work: 0.172 
  • R-Value Observed: 0.172 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 93α = 90
b = 72.5β = 90
c = 62.18γ = 90
Software Package:
Software NamePurpose
CNSrefinement
MOSFLMdata reduction
CCP4data scaling
CNSphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-06-07
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Atomic model, Data collection, Derived calculations, Structure summary