1ECE

ACIDOTHERMUS CELLULOLYTICUS ENDOCELLULASE E1 CATALYTIC DOMAIN IN COMPLEX WITH A CELLOTETRAOSE


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.236 
  • R-Value Work: 0.179 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Crystal structure of thermostable family 5 endocellulase E1 from Acidothermus cellulolyticus in complex with cellotetraose.

Sakon, J.Adney, W.S.Himmel, M.E.Thomas, S.R.Karplus, P.A.

(1996) Biochemistry 35: 10648-10660

  • DOI: 10.1021/bi9604439

  • PubMed Abstract: 
  • The crystal structure of the catalytic domain of the thermostable endocellulase E1 from Acidothermus cellulolyticus in complex with cellotetraose has been solved by multiple isomorphous replacement and refined at 2.4 A resolution to an R-factor of 0. ...

    The crystal structure of the catalytic domain of the thermostable endocellulase E1 from Acidothermus cellulolyticus in complex with cellotetraose has been solved by multiple isomorphous replacement and refined at 2.4 A resolution to an R-factor of 0.18 (Rfree = 0.24). E1cd is a member of the 4/7 superfamily of hydrolases, and as expected, its structure is an (alpha/beta)8 barrel, which constitutes a prototype for family 5-subfamily 1 cellulases. The cellotetraose molecule binds in a manner consistent with the expected Michaelis complex for the glycosylation half-reaction and reveals that all eight residues conserved in family 5 enzymes are involved in recognition of the glycosyl group attacked during cleavage. Whereas only three residues are conserved in the whole 4/7 superfamily (the Asn/Glu duo and the Glu from which the name is derived), structural comparisons show that all eight residues conserved in family 5 have functional equivalents in the other 4/7 superfamily members, strengthening the case that mechanistic details are conserved throughout the superfamily. On the basis of the structure, a detailed sequence of physical steps of the cleavage mechanism is proposed. A close approach of two key glutamate residues provides an elegant mechanism for the shift in the pKa of the acid/base for the glycosylation and deglycosylation half-reactions. Finally, purely structural based comparisons are used to show that significant differences exist in structural similarity scores resulting from different methods and suggest that caution should be exercised in interpreting such results in terms of implied evolutional relationships.


    Organizational Affiliation

    Section of Biochemistry, Molecular and Cell Biology, Cornell University, Ithaca, New York 14853, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
ENDOCELLULASE E1
A, B
358Acidothermus cellulolyticus (strain ATCC 43068 / 11B)EC: 3.2.1.4
Find proteins for P54583 (Acidothermus cellulolyticus (strain ATCC 43068 / 11B))
Go to UniProtKB:  P54583
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
BGC
Query on BGC

Download SDF File 
Download CCD File 
A, B
BETA-D-GLUCOSE
C6 H12 O6
WQZGKKKJIJFFOK-VFUOTHLCSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.236 
  • R-Value Work: 0.179 
  • Space Group: P 32 2 1
Unit Cell:
Length (Å)Angle (°)
a = 97.130α = 90.00
b = 97.130β = 90.00
c = 258.710γ = 120.00
Software Package:
Software NamePurpose
X-PLORrefinement
X-PLORmodel building
X-PLORphasing

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1996-10-14
    Type: Initial release
  • Version 1.1: 2008-03-24
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance