5MVH

Glycoside Hydrolase BACCELL_00856


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.214 
  • R-Value Work: 0.167 
  • R-Value Observed: 0.169 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Unusual active site location and catalytic apparatus in a glycoside hydrolase family.

Munoz-Munoz, J.Cartmell, A.Terrapon, N.Henrissat, B.Gilbert, H.J.

(2017) Proc Natl Acad Sci U S A 114: 4936-4941

  • DOI: 10.1073/pnas.1701130114
  • Primary Citation of Related Structures:  
    5MUK, 5MUL, 5MUM, 5MVH

  • PubMed Abstract: 
  • The human gut microbiota use complex carbohydrates as major nutrients. The requirement for an efficient glycan degrading systems exerts a major selection pressure on this microbial community. Thus, we propose that these bacteria represent a substantial resource for discovering novel carbohydrate active enzymes ...

    The human gut microbiota use complex carbohydrates as major nutrients. The requirement for an efficient glycan degrading systems exerts a major selection pressure on this microbial community. Thus, we propose that these bacteria represent a substantial resource for discovering novel carbohydrate active enzymes. To test this hypothesis, we focused on enzymes that hydrolyze rhamnosidic bonds, as cleavage of these linkages is chemically challenging and there is a paucity of information on l-rhamnosidases. Here we screened the activity of enzymes derived from the human gut microbiota bacterium Bacteroides thetaiotaomicron , which are up-regulated in response to rhamnose-containing glycans. We identified an α-l-rhamnosidase, BT3686, which is the founding member of a glycoside hydrolase (GH) family, GH145. In contrast to other rhamnosidases, BT3686 cleaved l-Rha-α1,4-d-GlcA linkages through a retaining double-displacement mechanism. The crystal structure of BT3686 showed that the enzyme displayed a type A seven-bladed β-propeller fold. Mutagenesis and crystallographic studies, including the structure of BT3686 in complex with the reaction product GlcA, revealed a location for the active site among β-propeller enzymes cited on the posterior surface of the rhamnosidase. In contrast to the vast majority of GH, the catalytic apparatus of BT3686 does not comprise a pair of carboxylic acid residues but, uniquely, a single histidine functions as the only discernable catalytic amino acid. Intriguingly, the histidine, His48, is not invariant in GH145; however, when engineered into structural homologs lacking the imidazole residue, α-l-rhamnosidase activity was established. The potential contribution of His48 to the catalytic activity of BT3686 is discussed.


    Organizational Affiliation

    Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom; harry.gilbert@ncl.ac.uk.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
BACCELL_00856A431Bacteroides cellulosilyticus DSM 14838Mutation(s): 0 
Gene Names: BACCELL_00856
UniProt
Find proteins for E2N9B1 (Bacteroides cellulosilyticus DSM 14838)
Explore E2N9B1 
Go to UniProtKB:  E2N9B1
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupE2N9B1
Protein Feature View
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.214 
  • R-Value Work: 0.167 
  • R-Value Observed: 0.169 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 52.842α = 90
b = 68.627β = 97.72
c = 52.88γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
XDSdata reduction
Aimlessdata scaling
PHASERphasing

Structure Validation

View Full Validation Report



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
European Research CouncilUnited Kingdom322280

Revision History  (Full details and data files)

  • Version 1.0: 2017-04-26
    Type: Initial release
  • Version 1.1: 2017-05-17
    Changes: Database references
  • Version 1.2: 2019-10-16
    Changes: Data collection