skip to main content

DOE PAGESDOE PAGES

Title: Bacterial expansins and related proteins from the world of microbes

The discovery of microbial expansins emerged from studies of the mechanism of plant cell growth and the molecular basis of plant cell wall extensibility. Expansins are wall-loosening proteins that are universal in the plant kingdom and are also found in a small set of phylogenetically diverse bacteria, fungi, and other organisms, most of which colonize plant surfaces. They loosen plant cell walls without detectable lytic activity. Bacterial expansins have attracted considerable attention recently for their potential use in cellulosic biomass conversion for biofuel production, as a means to disaggregate cellulosic structures by nonlytic means (“amorphogenesis”). Evolutionary analysis indicates that microbial expansins originated by multiple horizontal gene transfers from plants. Crystallographic analysis of BsEXLX1, the expansin from Bacillus subtilis, shows that microbial expansins consist of two tightly packed domains: the N-terminal domain D1 has a double-ψ β-barrel fold similar to glycosyl hydrolase family-45 enzymes but lacks catalytic residues usually required for hydrolysis; the C-terminal domain D2 has a unique β-sandwich fold with three co-linear aromatic residues that bind β-1,4-glucans by hydrophobic interactions. Genetic deletion of expansin in Bacillus and Clavibacter cripples their ability to colonize plant tissues. In this paper, we assess reports that expansin addition enhances cellulose breakdown by cellulasemore » and compare expansins with distantly related proteins named swollenin, cerato-platanin, and loosenin. Finally, we end in a speculative vein about the biological roles of microbial expansins and their potential applications. Advances in this field will be aided by a deeper understanding of how these proteins modify cellulosic structures.« less
Authors:
 [1] ;  [2] ;  [3]
  1. J.R. Simplot Co., Boise, ID (United States)
  2. California State Univ. (CalState), Fullerton, CA (United States)
  3. Penn State Univ., University Park, PA (United States)
Publication Date:
Grant/Contract Number:
FG02-84ER13179
Type:
Accepted Manuscript
Journal Name:
Applied Microbiology and Biotechnology
Additional Journal Information:
Journal Volume: 99; Journal Issue: 9; Journal ID: ISSN 0175-7598
Publisher:
Springer
Research Org:
Pennsylvania State Univ., University Park, PA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; amorphogenesis; biofuels; cellulase synergism; expansin; plant-microbe interactions; swollenin
OSTI Identifier:
1343258

Georgelis, Nikolaos, Nikolaidis, Nikolas, and Cosgrove, Daniel J. Bacterial expansins and related proteins from the world of microbes. United States: N. p., Web. doi:10.1007/s00253-015-6534-0.
Georgelis, Nikolaos, Nikolaidis, Nikolas, & Cosgrove, Daniel J. Bacterial expansins and related proteins from the world of microbes. United States. doi:10.1007/s00253-015-6534-0.
Georgelis, Nikolaos, Nikolaidis, Nikolas, and Cosgrove, Daniel J. 2015. "Bacterial expansins and related proteins from the world of microbes". United States. doi:10.1007/s00253-015-6534-0. https://www.osti.gov/servlets/purl/1343258.
@article{osti_1343258,
title = {Bacterial expansins and related proteins from the world of microbes},
author = {Georgelis, Nikolaos and Nikolaidis, Nikolas and Cosgrove, Daniel J.},
abstractNote = {The discovery of microbial expansins emerged from studies of the mechanism of plant cell growth and the molecular basis of plant cell wall extensibility. Expansins are wall-loosening proteins that are universal in the plant kingdom and are also found in a small set of phylogenetically diverse bacteria, fungi, and other organisms, most of which colonize plant surfaces. They loosen plant cell walls without detectable lytic activity. Bacterial expansins have attracted considerable attention recently for their potential use in cellulosic biomass conversion for biofuel production, as a means to disaggregate cellulosic structures by nonlytic means (“amorphogenesis”). Evolutionary analysis indicates that microbial expansins originated by multiple horizontal gene transfers from plants. Crystallographic analysis of BsEXLX1, the expansin from Bacillus subtilis, shows that microbial expansins consist of two tightly packed domains: the N-terminal domain D1 has a double-ψ β-barrel fold similar to glycosyl hydrolase family-45 enzymes but lacks catalytic residues usually required for hydrolysis; the C-terminal domain D2 has a unique β-sandwich fold with three co-linear aromatic residues that bind β-1,4-glucans by hydrophobic interactions. Genetic deletion of expansin in Bacillus and Clavibacter cripples their ability to colonize plant tissues. In this paper, we assess reports that expansin addition enhances cellulose breakdown by cellulase and compare expansins with distantly related proteins named swollenin, cerato-platanin, and loosenin. Finally, we end in a speculative vein about the biological roles of microbial expansins and their potential applications. Advances in this field will be aided by a deeper understanding of how these proteins modify cellulosic structures.},
doi = {10.1007/s00253-015-6534-0},
journal = {Applied Microbiology and Biotechnology},
number = 9,
volume = 99,
place = {United States},
year = {2015},
month = {4}
}