5J14

Crystal structure of endoglycoceramidase I from Rhodococ-cus equi in complex with GM3


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.92 Å
  • R-Value Free: 0.204 
  • R-Value Work: 0.167 

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Literature

Structural Insights into the Broad Substrate Specificity of a Novel Endoglycoceramidase I Belonging to a New Subfamily of GH5 Glycosidases

Han, Y.B.Chen, L.Q.Li, Z.Tan, Y.M.Feng, Y.Yang, G.Y.

(2017) J Biol Chem 292: 4789-4800

  • DOI: https://doi.org/10.1074/jbc.M116.763821
  • Primary Citation of Related Structures:  
    5CCU, 5J14, 5J7Z

  • PubMed Abstract: 

    Endoglycoceramidases (EGCases) specifically hydrolyze the glycosidic linkage between the oligosaccharide and the ceramide moieties of various glycosphingolipids, and they have received substantial attention in the emerging field of glycosphingolipidology. However, the mechanism regulating the strict substrate specificity of these GH5 glycosidases has not been identified. In this study, we report a novel EGCase I from Rhodococcus equi 103S (103S_EGCase I) with remarkably broad substrate specificity. Based on phylogenetic analyses, the enzyme may represent a new subfamily of GH5 glycosidases. The X-ray crystal structures of 103S_EGCase I alone and in complex with its substrates monosialodihexosylganglioside (GM3) and monosialotetrahexosylganglioside (GM1) enabled us to identify several structural features that may account for its broad specificity. Compared with EGCase II from Rhodococcus sp. M-777 (M777_EGCase II), which possesses strict substrate specificity, 103S_EGCase I possesses a longer α7-helix and a shorter loop 4, which forms a larger substrate-binding pocket that could accommodate more extended oligosaccharides. In addition, loop 2 and loop 8 of the enzyme adopt a more open conformation, which also enlarges the oligosaccharide-binding cavity. Based on this knowledge, a rationally designed experiment was performed to examine the substrate specificity of EGCase II. The truncation of loop 4 in M777_EGCase II increased its activity toward GM1 (163%). Remarkably, the S63G mutant of M777_EGCase II showed a broader substrate spectra and significantly increased activity toward bulky substrates (up to >1370-fold for fucosyl-GM1). Collectively, the results presented here reveal the exquisite substrate recognition mechanism of EGCases and provide an opportunity for further engineering of these enzymes.


  • Organizational Affiliation

    From the State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Putative secreted endoglycosylceramidase
A, B
500Prescottella equi 103SMutation(s): 1 
Gene Names: REQ_38260
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
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  • Reference Sequence
Oligosaccharides

Help

Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
N-acetyl-alpha-neuraminic acid-(2-3)-beta-D-galactopyranose-(1-4)-beta-D-glucopyranose
C
3N/A
Glycosylation Resources
GlyTouCan:  G91237TK
GlyCosmos:  G91237TK
GlyGen:  G91237TK
Entity ID: 3
MoleculeChains Length2D Diagram Glycosylation3D Interactions
beta-D-galactopyranose-(1-4)-beta-D-glucopyranose
D
2N/A
Glycosylation Resources
GlyTouCan:  G84224TW
GlyCosmos:  G84224TW
GlyGen:  G84224TW
Biologically Interesting Molecules (External Reference) 1 Unique
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.92 Å
  • R-Value Free: 0.204 
  • R-Value Work: 0.167 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 192.521α = 90
b = 49.053β = 114.19
c = 120.135γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
HKL-2000data reduction
HKL-2000data scaling
MOLREPphasing

Structure Validation

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Entry History 

Deposition Data

  • Released Date: 2016-04-27 
  • Deposition Author(s): Chen, L.

Revision History  (Full details and data files)

  • Version 1.0: 2016-04-27
    Type: Initial release
  • Version 1.1: 2017-04-05
    Changes: Database references
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Atomic model, Data collection, Derived calculations, Structure summary
  • Version 2.1: 2023-11-08
    Changes: Data collection, Database references, Derived calculations, Refinement description, Structure summary