1BYA

CRYSTAL STRUCTURES OF SOYBEAN BETA-AMYLASE REACTED WITH BETA-MALTOSE AND MALTAL: ACTIVE SITE COMPONENTS AND THEIR APPARENT ROLE IN CATALYSIS


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Work: 0.169 
  • R-Value Observed: 0.169 

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This is version 1.5 of the entry. See complete history


Literature

Crystal structures of soybean beta-amylase reacted with beta-maltose and maltal: active site components and their apparent roles in catalysis.

Mikami, B.Degano, M.Hehre, E.J.Sacchettini, J.C.

(1994) Biochemistry 33: 7779-7787

  • Primary Citation of Related Structures:  
    1BYA, 1BYB, 1BYC, 1BYD

  • PubMed Abstract: 

    The crystal structures of catalytically competent soybean beta-amylase, unliganded and bathed with small substrates (beta-maltose, maltal), were determined at 1.9-2.2-A resolution. Two molecules of beta-maltose substrate bind to the protein in tandem, with some maltotetraose enzymic condensation product sharing the same binding sites. The beta-amylase soaked with maltal shows a similar arrangement of two bound molecules of 2-deoxymaltose, the enzymic hydration product. In each case the nonreducing ends of the saccharide ligands are oriented toward the base of the protein's active site pocket. The catalytic center, located between the bound disaccharides and found deeper in the pocket than where the inhibitor alpha-cyclodextrin binds, is characterized by the presence of oppositely disposed carboxyl groups of two conserved glutamic acid residues. The OE2 carboxyl of Glu 186 is below the plane of the penultimate glucose residue (Glc 2) of bound maltotetraose, 2.6 A from the oxygen atom of that ligand's penultimate alpha-1,4-glucosidic linkage. The OE2 carboxyl of Glu 380 lies above the plane of Glc 2, 2.8 A from the O-1 atom of the more deeply bound beta-maltose. Saccharide binding does not alter the spatial coordinates of these two carboxyl groups or the overall conformation of the 57-kDa protein. However, the saccharide complexes of the active enzyme are associated with a significant (10 A) local conformational change in a peptide segment of a loop (L3) that borders the active site pocket.(ABSTRACT TRUNCATED AT 250 WORDS)


  • Organizational Affiliation

    Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
BETA-AMYLASE495Glycine maxMutation(s): 0 
EC: 3.2.1.2
UniProt
Find proteins for P10538 (Glycine max)
Explore P10538 
Go to UniProtKB:  P10538
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP10538
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download Ideal Coordinates CCD File 
B [auth A]SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Work: 0.169 
  • R-Value Observed: 0.169 
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 86.2α = 90
b = 86.2β = 90
c = 144.2γ = 120
Software Package:
Software NamePurpose
X-PLORmodel building
TNTrefinement
X-PLORrefinement
X-PLORphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1994-07-31
    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: 2019-07-17
    Changes: Data collection, Other, Refinement description
  • Version 1.4: 2019-08-14
    Changes: Data collection, Refinement description
  • Version 1.5: 2024-02-07
    Changes: Data collection, Database references, Derived calculations