Biological Assembly 1  

 3D View: Structure | Electron Density | Ligand Interaction

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors.

Biological Assembly 2  

 3D View: Structure | Electron Density | Ligand Interaction

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 2 assigned by authors.

Macromolecule Content

• Total Structure Weight: 134.59 kDa 
• Atom Count: 11074 
• Modelled Residue Count: 1210 
• Deposited Residue Count: 1210 
• Unique protein chains: 1

1TF4

ENDO/EXOCELLULASE FROM THERMOMONOSPORA

• DOI: 10.2210/pdb1TF4/pdb

• Classification: GLYCOSYL HYDROLASE
• Organism(s): Thermobifida fusca
• Expression System: Streptomyces lividans TK24
• Mutation(s): No 


• Deposited: 1997-05-30 Released: 1997-09-04 
• Deposition Author(s): Sakon, J., Wilson, D.B., Karplus, P.A.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.90 Å
• R-Value Free: 0.250 
• R-Value Work: 0.200 
• R-Value Observed: 0.200 

Literature

Structure and mechanism of endo/exocellulase E4 from Thermomonospora fusca.

Sakon, J., Irwin, D., Wilson, D.B., Karplus, P.A.

(1997) Nat Struct Biol 4: 810-818

• PubMed: 9334746 
• DOI: 10.1038/nsb1097-810
• Primary Citation of Related Structures:  
  4TF4, 1JS4, 1TF4, 3TF4


• PubMed Abstract: 
  

Cellulase E4 from Thermomonospora fusca is unusual in that it has characteristics of both exo- and endo-cellulases. Here we report the crystal structure of a 68K M(r) fragment of E4 (E4-68) at 1.9 A resolution. E4-68 contains both a family 9 catalytic domain, exhibiting an (alpha/alpha)6 barrel fold, and a family III cellulose binding domain, having an antiparallel beta-sandwich fold. While neither of these folds is novel, E4-68 provides the first cellulase structure having interacting catalytic and cellulose binding domains. The complexes of E4-68 with cellopentaose, cellotriose and cellobiose reveal conformational changes associated with ligand binding and allow us to propose a catalytic mechanism for family 9 enzymes. We also provide evidence that E4 has two novel characteristics: first it combines exo- and endo-activities and second, when it functions as an exo-cellulase, it cleaves off cellotetraose units.

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Organizational Affiliation: 

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

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
T. FUSCA ENDO/EXO-CELLULASE E4 CATALYTIC DOMAIN AND CELLULOSE-BINDING DOMAIN	A, B	605	Thermobifida fusca	Mutation(s): 0  Gene Names: BAMH1-PST1 FRAGMENT OF T. FUSC, celD EC: 3.2.1.4
Find proteins for P26221 (Thermobifida fusca) Explore P26221  Go to UniProtKB:  P26221

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
CA	C [auth A], D [auth A], E [auth B], F [auth B]	CALCIUM ION Ca BHPQYMZQTOCNFJ-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.90 Å
• R-Value Free: 0.250 
• R-Value Work: 0.200 
• R-Value Observed: 0.200 
• Space Group: P 4₁ 2₁ 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 145.68	α = 90
b = 145.68	β = 90
c = 157.08	γ = 90

Software Package:

Software Name	Purpose
SCALEPACK	data scaling
PHASES	phasing
X-PLOR	model building
X-PLOR	refinement
X-PLOR	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 1997-05-30 
• Released Date: 1997-09-04 
Deposition Author(s): Sakon, J., Wilson, D.B., Karplus, P.A.

Revision History  

• Version 1.0: 1997-09-04
  Type: Initial release
  
• Version 1.1: 2008-03-24
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance