2E4T

Crystal structure of Cel44A, GH family 44 endoglucanase from Clostridium thermocellum

• PDB DOI: https://doi.org/10.2210/pdb2E4T/pdb

• Classification: HYDROLASE
• Organism(s): Acetivibrio thermocellus
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2006-12-16 Released: 2007-09-18 
• Deposition Author(s): Kitago, Y., Karita, S., Watanabe, N., Sakka, K., Tanaka, I.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 0.96 Å
• R-Value Free: 0.146 
• R-Value Work: 0.133 
• R-Value Observed: 0.133 

Literature

Crystal structure of Cel44A, a glycoside hydrolase family 44 endoglucanase from Clostridium thermocellum.

Kitago, Y., Karita, S., Watanabe, N., Kamiya, M., Aizawa, T., Sakka, K., Tanaka, I.

(2007) J Biol Chem 282: 35703-35711

• PubMed: 17905739 
• DOI: https://doi.org/10.1074/jbc.M706835200
• Primary Citation of Related Structures:  
  2E0P, 2E4T, 2EEX, 2EJ1, 2EO7, 2EQD


• PubMed Abstract: 
  

  The crystal structure of Cel44A, which is one of the enzymatic components of the cellulosome of Clostridium thermocellum, was solved at a resolution of 0.96 A. This enzyme belongs to glycoside hydrolase family (GH family) 44. The structure reveals that Cel44A consists of a TIM-like barrel domain and a beta-sandwich domain. The wild-type and the E186Q mutant structures complexed with substrates suggest that two glutamic acid residues, Glu(186) and Glu(359), are the active residues of the enzyme. Biochemical experiments were performed to confirm this idea. The structural features indicate that GH family 44 belongs to clan GH-A and that the reaction catalyzed by Cel44A is retaining type hydrolysis. The stereochemical course of hydrolysis was confirmed by a (1)H NMR experiment using the reduced cellooligosaccharide as a substrate.

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Organizational Affiliation: 

Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo 0600810, Japan.

Biological Assembly 1  

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

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 58.2 kDa 
• Atom Count: 4,698 
• Modelled Residue Count: 509 
• Deposited Residue Count: 519 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Endoglucanase	A	519	Acetivibrio thermocellus	Mutation(s): 0  Gene Names: celJ EC: 3.2.1.4 (PDB Primary Data), 3.2.1.151 (PDB Primary Data)
UniProt
Find proteins for P71140 (Acetivibrio thermocellus) Explore P71140  Go to UniProtKB:  P71140

Small Molecules

Ligands 4 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
GOL	E [auth A], F [auth A], G [auth A], H [auth A]	GLYCEROL C3 H8 O3 PEDCQBHIVMGVHV-UHFFFAOYSA-N
ZN	B [auth A]	ZINC ION Zn PTFCDOFLOPIGGS-UHFFFAOYSA-N
CA	C [auth A]	CALCIUM ION Ca BHPQYMZQTOCNFJ-UHFFFAOYSA-N
CL	D [auth A]	CHLORIDE ION Cl VEXZGXHMUGYJMC-UHFFFAOYSA-M

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 0.96 Å
• R-Value Free: 0.146 
• R-Value Work: 0.133 
• R-Value Observed: 0.133 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 48.077	α = 90
b = 59.155	β = 90
c = 170.684	γ = 90

Software Package:

Software Name	Purpose
REFMAC	refinement
PF	data collection
DENZO	data reduction
SCALEPACK	data scaling
SHELXE	model building

Structure Validation

Entry History 

Deposition Data

• Released Date: 2007-09-18 
Deposition Author(s): Kitago, Y., Karita, S., Watanabe, N., Sakka, K., Tanaka, I.

Revision History  

• Version 1.0: 2007-09-18
  Type: Initial release
  
• Version 1.1: 2011-07-13
  Changes: Non-polymer description, Version format compliance
• Version 1.2: 2024-03-13
  Changes: Data collection, Database references, Derived calculations