4FG2

Crystal structure of Bacillus Subtilis expansin (EXLX1) in complex with cellotetraose

Summary for 4FG2

• Entry DOI: 10.2210/pdb4fg2/pdb
• Related: 2BH0 3D30 4FER 4FFT
• Related PRD ID: PRD_900011
• Descriptor: Expansin-yoaJ, beta-D-glucopyranose-(1-4)-beta-D-glucopyranose-(1-4)-beta-D-glucopyranose-(1-4)-beta-D-glucopyranose, ACETIC ACID, ... (4 entities in total)
• Functional Keywords: cellulose, cellulose-binding protein
• Biological source: Bacillus subtilis subsp. subtilis
• Cellular location: Secreted, cell wall : O34918
• Total number of polymer chains: 2
• Total formula weight: 46979.33

Authors

Georgelis, N.,Yennawar, N.H.,Cosgrove, D.J. (deposition date: 2012-06-02, release date: 2012-08-22, Last modification date: 2024-02-28)

Primary citation

Georgelis, N.,Yennawar, N.H.,Cosgrove, D.J.
Structural basis for entropy-driven cellulose binding by a type-A cellulose-binding module (CBM) and bacterial expansin.
Proc.Natl.Acad.Sci.USA, 109:14830-14835, 2012

PubMed Abstract: Components of modular cellulases, type-A cellulose-binding modules (CBMs) bind to crystalline cellulose and enhance enzyme effectiveness, but structural details of the interaction are uncertain. We analyzed cellulose binding by EXLX1, a bacterial expansin with ability to loosen plant cell walls and whose domain D2 has type-A CBM characteristics. EXLX1 strongly binds to crystalline cellulose via D2, whereas its affinity for soluble cellooligosaccharides is weak. Calorimetry indicated cellulose binding was largely entropically driven. We solved the crystal structures of EXLX1 complexed with cellulose-like oligosaccharides to find that EXLX1 binds the ligands through hydrophobic interactions of three linearly arranged aromatic residues in D2. The crystal structures revealed a unique form of ligand-mediated dimerization, with the oligosaccharide sandwiched between two D2 domains in opposite polarity. This report clarifies the molecular target of expansin and the specific molecular interactions of a type-A CBM with cellulose.

PubMed: 22927418
DOI: 10.1073/pnas.1213200109

Experimental method

X-RAY DIFFRACTION (2.099 Å)