Structure of the Starch Branching Enzyme I (BEI) from Oryza sativa L

Experimental Data Snapshot

  • Resolution: 1.90 Å
  • R-Value Free: 0.221 
  • R-Value Work: 0.181 
  • R-Value Observed: 0.183 

wwPDB Validation   3D Report Full Report

This is version 1.0 of the entry. See complete history


Crystal structure of the branching enzyme I (BEI) from Oryza sativa L with implications for catalysis and substrate binding.

Noguchi, J.Chaen, K.Vu, N.T.Akasaka, T.Shimada, H.Nakashima, T.Nishi, A.Satoh, H.Omori, T.Kakuta, Y.Kimura, M.

(2011) Glycobiology 21: 1108-1116

  • DOI: https://doi.org/10.1093/glycob/cwr049
  • Primary Citation of Related Structures:  
    3AMK, 3AML

  • PubMed Abstract: 

    Starch-branching enzyme catalyzes the cleavage of α-1, 4-linkages and the subsequent transfer of α-1,4 glucan to form an α-1,6 branch point in amylopectin. Sequence analysis of the rice-branching enzyme I (BEI) indicated a modular structure in which the central α-amylase domain is flanked on each side by the N-terminal carbohydrate-binding module 48 and the α-amylase C-domain. We determined the crystal structure of BEI at a resolution of 1.9 Å by molecular replacement using the Escherichia coli glycogen BE as a search model. Despite three modular structures, BEI is roughly ellipsoidal in shape with two globular domains that form a prominent groove which is proposed to serve as the α-polyglucan-binding site. Amino acid residues Asp344 and Glu399, which are postulated to play an essential role in catalysis as a nucleophile and a general acid/base, respectively, are located at a central cleft in the groove. Moreover, structural comparison revealed that in BEI, extended loop structures cause a narrowing of the substrate-binding site, whereas shortened loop structures make a larger space at the corresponding subsite in the Klebsiella pneumoniae pullulanase. This structural difference might be attributed to distinct catalytic reactions, transglycosylation and hydrolysis, respectively, by BEI and pullulanase.

  • Organizational Affiliation

    Laboratory of Structural Biology, Graduate School of Systems Life Sciences, Faculty of Agriculture, Kyushu University, Hakozaki 6-10-1, Fukuoka 812-8581, Japan.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Os06g0726400 protein702Oryza sativa Japonica GroupMutation(s): 0 
Gene Names: Os06g0726400SBE1
Find proteins for Q01401 (Oryza sativa subsp. japonica)
Explore Q01401 
Go to UniProtKB:  Q01401
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ01401
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.90 Å
  • R-Value Free: 0.221 
  • R-Value Work: 0.181 
  • R-Value Observed: 0.183 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 43.894α = 90
b = 114.854β = 93.98
c = 66.819γ = 90
Software Package:
Software NamePurpose
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-09-28
    Type: Initial release