The X-ray Crystallographic Structure of Branching Enzyme

Experimental Data Snapshot

  • Resolution: 2.30 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.200 

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The X-ray crystallographic structure of Escherichia coli branching enzyme

Abad, M.C.Binderup, K.Rios-Steiner, J.Arni, R.K.Preiss, J.Geiger, J.H.

(2002) J Biol Chem 277: 42164-42170

  • DOI: https://doi.org/10.1074/jbc.M205746200
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Branching enzyme catalyzes the formation of alpha-1,6 branch points in either glycogen or starch. We report the 2.3-A crystal structure of glycogen branching enzyme from Escherichia coli. The enzyme consists of three major domains, an NH(2)-terminal seven-stranded beta-sandwich domain, a COOH-terminal domain, and a central alpha/beta-barrel domain containing the enzyme active site. While the central domain is similar to that of all the other amylase family enzymes, branching enzyme shares the structure of all three domains only with isoamylase. Oligosaccharide binding was modeled for branching enzyme using the enzyme-oligosaccharide complex structures of various alpha-amylases and cyclodextrin glucanotransferase and residues were implicated in oligosaccharide binding. While most of the oligosaccharides modeled well in the branching enzyme structure, an approximate 50 degrees rotation between two of the glucose units was required to avoid steric clashes with Trp(298) of branching enzyme. A similar rotation was observed in the mammalian alpha-amylase structure caused by an equivalent tryptophan residue in this structure. It appears that there are two binding modes for oligosaccharides in these structures depending on the identity and location of this aromatic residue.

  • Organizational Affiliation

    Department of Chemistry, Michigan State University, East Lansing 48824, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
1,4-alpha-glucan Branching Enzyme
A, B, C, D
617Escherichia coliMutation(s): 0 
Find proteins for P07762 (Escherichia coli (strain K12))
Explore P07762 
Go to UniProtKB:  P07762
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP07762
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.30 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.200 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 91.475α = 90
b = 102.619β = 91.45
c = 185.06γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
SCALEPACKdata scaling
dphasesmodel building
HKL-2000data reduction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2002-09-18
    Type: Initial release
  • Version 1.1: 2008-04-28
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2022-12-21
    Changes: Database references
  • Version 1.4: 2024-05-22
    Changes: Data collection