2WO4: 3b' Carbohydrate-binding Module From The Cel9v Glycoside Hydrolase From Clostridium Thermocellum, In-house Data

Citation:
Abstract
Family 3 carbohydrate-binding modules (CBM3s) are associated with both cellulosomal scaffoldins and family 9 glycoside hydrolases (GH9s), which are multi-modular enzymes that act on cellulosic substrates. CBM3s bind cellulose. X-ray crystal structures of these modules have established an accepted cellulose-binding mechanism based on stacking interactions between the sugar rings of cellulose and a planar array of aromatic residues located on the CBM3 surface. These planar-strip residues are generally highly conserved, although some CBM3 sequences lack one or more of these residues. In particular, CBM3b' from Clostridium thermocellum Cel9V exhibits such sequence changes and fails to bind cellulosic substrates. A crystallographic investigation of CBM3b' has been initiated in order to understand the structural reason(s) for this inability. CBM3b' crystallized in space group C222(1) (diffraction was obtained to 2.0 A resolution in-house) with three independent molecules in the asymmetric unit and in space group P4(1)2(1)2 (diffraction was obtained to 1.79 A resolution in-house and to 1.30 A resolution at a synchrotron) with one molecule in the asymmetric unit. The molecular structure of Cel9V CBM3b' revealed that in addition to the loss of several cellulose-binding residues in the planar strip, changes in the backbone create a surface 'hump' which could interfere with the formation of cellulose-protein surface interactions and thus prevent binding to crystalline cellulose.
PDB ID: 2WO4Download
MMDB ID: 79027
PDB Deposition Date: 2009/7/21
Updated in MMDB: 2009/12
Experimental Method:
x-ray diffraction
Resolution: 1.85  Å
Source Organism:
Similar Structures:
Biological Unit for 2WO4: monomeric; determined by author and by software (PISA)
Molecular Components in 2WO4
Label Count Molecule
Protein (1 molecule)
1
Glycoside Hydrolase, Family 9
Molecule annotation
Chemicals (3 molecules)
1
1
2
1
3
1
* Click molecule labels to explore molecular sequence information.

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