Structural basis for entropy-driven cellulose binding by a type-A cellulose-binding module (CBM) and bacterial expansin

Research output: Contribution to journalArticle

80 Citations (Scopus)

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.

Original languageEnglish (US)
Pages (from-to)14830-14835
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume109
Issue number37
DOIs
StatePublished - Sep 11 2012

Fingerprint

Entropy
Cellulose
Oligosaccharides
Ligands
Cellulases
Calorimetry
Plant Cells
Dimerization
Hydrophobic and Hydrophilic Interactions
Cell Wall
Enzymes

All Science Journal Classification (ASJC) codes

  • General

Cite this

@article{fccbd22216114c70a40f4a09e396216d,
title = "Structural basis for entropy-driven cellulose binding by a type-A cellulose-binding module (CBM) and bacterial expansin",
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.",
author = "Nikolaos Georgelis and Yennawar, {Neela H.} and Cosgrove, {Daniel J.}",
year = "2012",
month = "9",
day = "11",
doi = "10.1073/pnas.1213200109",
language = "English (US)",
volume = "109",
pages = "14830--14835",
journal = "Proceedings of the National Academy of Sciences of the United States of America",
issn = "0027-8424",
number = "37",

}

TY - JOUR

T1 - Structural basis for entropy-driven cellulose binding by a type-A cellulose-binding module (CBM) and bacterial expansin

AU - Georgelis, Nikolaos

AU - Yennawar, Neela H.

AU - Cosgrove, Daniel J.

PY - 2012/9/11

Y1 - 2012/9/11

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=84866279744&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84866279744&partnerID=8YFLogxK

U2 - 10.1073/pnas.1213200109

DO - 10.1073/pnas.1213200109

M3 - Article

C2 - 22927418

AN - SCOPUS:84866279744

VL - 109

SP - 14830

EP - 14835

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

SN - 0027-8424

IS - 37

ER -