Maltose phosphorylase from Lactobacillus brevis

Experimental Data Snapshot

  • Resolution: 2.15 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.186 
  • R-Value Observed: 0.186 

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Crystal Structure of Maltose Phosphorylase from Lactobacillus Brevis: Unexpected Evolutionary Relationship with Glucoamylases.

Egloff, M.-P.Uppenberg, J.Haalck, L.Van Tilbeurgh, H.

(2001) Structure 9: 689

  • DOI: https://doi.org/10.1016/s0969-2126(01)00626-8
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Maltose phosphorylase (MP) is a dimeric enzyme that catalyzes the conversion of maltose and inorganic phosphate into beta-D-glucose-1-phosphate and glucose without requiring any cofactors, such as pyridoxal phosphate. The enzyme is part of operons that are involved in maltose/malto-oligosaccharide metabolism. Maltose phosphorylases have been classified in family 65 of the glycoside hydrolases. No structure is available for any member of this family. We report here the 2.15 A resolution crystal structure of the MP from Lactobacillus brevis in complex with the cosubstrate phosphate. This represents the first structure of a disaccharide phosphorylase. The structure consists of an N-terminal complex beta sandwich domain, a helical linker, an (alpha/alpha)6 barrel catalytic domain, and a C-terminal beta sheet domain. The (alpha/alpha)6 barrel has an unexpected strong structural and functional analogy with the catalytic domain of glucoamylase from Aspergillus awamori. The only conserved glutamate of MP (Glu487) superposes onto the catalytic residue Glu179 of glucoamylase and likely represents the general acid catalyst. The phosphate ion is bound in a pocket facing the carboxylate of Glu487 and is ideally positioned for nucleophilic attack of the anomeric carbon atom. This site is occupied by the catalytic base carboxylate in glucoamylase. These observations strongly suggest that maltose phosphorylase has evolved from glucoamylase. MP has probably conserved one carboxylate group for acid catalysis and has exchanged the catalytic base for a phosphate binding pocket. The relative positions of the acid catalytic group and the bound phosphate are compatible with a direct-attack mechanism of a glycosidic bond by phosphate, in accordance with inversion of configuration at the anomeric carbon as observed for this enzyme.

  • Organizational Affiliation

    Architecture et Fonction des Macromolécules Biologiques, Centre National de la Recherche Scientifique, Unite Mixte de Recherche 6098, Université d'Aix-Marseille, I et II, Case 925, 13288, Marseille, France.

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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
754Levilactobacillus brevisMutation(s): 0 
Find proteins for Q7SIE1 (Levilactobacillus brevis)
Explore Q7SIE1 
Go to UniProtKB:  Q7SIE1
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ7SIE1
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on PO4

Download Ideal Coordinates CCD File 
O4 P
Query on K

Download Ideal Coordinates CCD File 
C [auth A],
E [auth B]
Experimental Data & Validation

Experimental Data

  • Resolution: 2.15 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.186 
  • R-Value Observed: 0.186 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 83.75α = 90
b = 102.5β = 111.3
c = 114γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2001-09-05
    Type: Initial release
  • Version 1.1: 2012-06-13
    Changes: Atomic model, Database references, Derived calculations, Non-polymer description, Other, Refinement description, Version format compliance
  • Version 1.2: 2024-05-08
    Changes: Data collection, Database references, Derived calculations