1V3H

The roles of Glu186 and Glu380 in the catalytic reaction of soybean beta-amylase


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.181 
  • R-Value Work: 0.163 
  • R-Value Observed: 0.163 

wwPDB Validation 3D Report Full Report



Literature

The Roles of Glu186 and Glu380 in the Catalytic Reaction of Soybean beta-Amylase.

Kang, Y.N.Adachi, M.Utsumi, S.Mikami, B.

(2004) J Mol Biol 339: 1129-1140

  • DOI: 10.1016/j.jmb.2004.04.029
  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • It has previously been suggested that the glutamic acid residues Glu186 and Glu380 of soybean beta-amylase play critical roles as a general acid and a general base catalyst, respectively. In order to confirm the roles of Glu186 and Glu380, each resid ...

    It has previously been suggested that the glutamic acid residues Glu186 and Glu380 of soybean beta-amylase play critical roles as a general acid and a general base catalyst, respectively. In order to confirm the roles of Glu186 and Glu380, each residue was mutated to a glutamine residue and the crystal structures of the substrate (E186Q/maltopentaose) and product (E380Q/maltose) complexes were determined at resolutions of 1.6 Angstrom and 1.9 Angstrom, respectively. Both mutant enzymes exhibited 16,000- and 37,000-fold decreased activity relative to that of the wild-type enzyme. The crystal structure of the E186Q/maltopentaose complex revealed an unambiguous five-glucose unit at subsites -2 to +3. Two maltose molecules bind on subsites -2 to -1 and +2 to +3 in the E380Q/maltose complex, whereas they bind in tandem to -2 to -1 and +1 to +2 in the wild-type/maltose complex. The conformation of the glucose residue at subsite -1 was identified as a stable (4)C(1) alpha-anomer in the E380Q/maltose complex, whereas a distorted ring conformation was observed in the wild-type/maltose complex. The side-chain movement of Gln380 to the position of a putative attacking water molecule seen in the wild-type enzyme caused the inactivation of the E380Q mutant and an altered binding pattern of maltose molecules. These results confirm the critical roles played by Glu186 in the donation of a proton to the glycosidic oxygen of the substrate, and by Glu380 in the activation of an attacking water molecule. The observed difference between the backbones of E186Q/maltopentaose and E380Q/maltose in terms of Thr342 suggests that the side-chain of Thr342 may stabilize the deprotonated form of Glu186 after the cleavage of the glycosidic bond.


    Organizational Affiliation

    Laboratory of Food Quality Design and Development, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011, Japan.



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Beta-amylaseA495Glycine maxMutation(s): 2 
Gene Names: BMY1
EC: 3.2.1.2
Find proteins for P10538 (Glycine max)
Explore P10538 
Go to UniProtKB:  P10538
Protein Feature View
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  • Reference Sequence
Oligosaccharides
Entity ID: 2
MoleculeChainsChain Length2D Diagram Glycosylation
alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose
N/A
5 N/A
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.181 
  • R-Value Work: 0.163 
  • R-Value Observed: 0.163 
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 85.379α = 90
b = 85.379β = 90
c = 143.959γ = 120
Software Package:
Software NamePurpose
CNSrefinement
HKL-2000data reduction
SCALEPACKdata scaling
CNSphasing

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-06-22
    Type: Initial release
  • Version 1.1: 2008-04-27
    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: Atomic model, Data collection, Derived calculations, Structure summary