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Structural insights into the inhibition of cellobiohydrolase Cel7A by xylo-oligosaccharides

Momeni, Majid Haddad; Ubhayasekera, Wimal LU ; Sandgren, Mats; Stahlberg, Jerry and Hansson, Henrik (2015) In The FEBS Journal 282(11). p.2167-2177
Abstract
The filamentous fungus Hypocreajecorina (anamorph of Trichodermareesei) is the predominant source of enzymes for industrial saccharification of lignocellulose biomass. The major enzyme, cellobiohydrolase Cel7A, constitutes nearly half of the total protein in the secretome. The performance of such enzymes is susceptible to inhibition by compounds liberated by physico-chemical pre-treatment if the biomass is kept unwashed. Xylan and xylo-oligosaccharides (XOS) have been proposed to play a key role in inhibition of cellobiohydrolases of glycoside hydrolase family7. To elucidate the mechanism behind this inhibition at a molecular level, we used X-ray crystallography to determine structures of H.jecorina Cel7A in complex with XOS. Structures... (More)
The filamentous fungus Hypocreajecorina (anamorph of Trichodermareesei) is the predominant source of enzymes for industrial saccharification of lignocellulose biomass. The major enzyme, cellobiohydrolase Cel7A, constitutes nearly half of the total protein in the secretome. The performance of such enzymes is susceptible to inhibition by compounds liberated by physico-chemical pre-treatment if the biomass is kept unwashed. Xylan and xylo-oligosaccharides (XOS) have been proposed to play a key role in inhibition of cellobiohydrolases of glycoside hydrolase family7. To elucidate the mechanism behind this inhibition at a molecular level, we used X-ray crystallography to determine structures of H.jecorina Cel7A in complex with XOS. Structures with xylotriose, xylotetraose and xylopentaose revealed a predominant binding mode at the entrance of the substrate-binding tunnel of the enzyme, in which each xylose residue is shifted similar to 2.4 angstrom towards the catalytic center compared with binding of cello-oligosaccharides. Furthermore, partial occupancy of two consecutive xylose residues at subsites -2 and -1 suggests an alternative binding mode for XOS in the vicinity of the catalytic center. Interestingly, the -1 xylosyl unit exhibits an open aldehyde conformation in one of the structures and a ring-closed pyranoside in another complex. Complementary inhibition studies with p-nitrophenyl lactoside as substrate indicate mixed inhibition rather than pure competitive inhibition. DatabaseThe atomic coordinates and structure factors are available in the Protein Data Bank under accession number (H. jecorina Cel7A E212Q variant, complex with xylotriose), (H. jecorina Cel7A E217Q variant, complex with xylotriose), (H. jecorina Cel7A E212Q variant, complex with xylopentaose), (H. jecorina Cel7A E217Q variant, complex with xylopentaose), (wild-type H. jecorina Cel7A, complex with xylopentaose) and (H. jecorina Cel7A E217Q variant, complex with xylotetraose). (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
biomass degradation, cellobiose, cellulase, inhibition, xylooligosaccharide
in
The FEBS Journal
volume
282
issue
11
pages
2167 - 2177
publisher
Federation of European Neuroscience Societies and Blackwell Publishing Ltd
external identifiers
  • wos:000355664000008
  • scopus:84930658710
ISSN
1742-464X
DOI
10.1111/febs.13265
language
English
LU publication?
yes
id
cde1e65b-02c1-4e09-912e-77618b6ddc97 (old id 7612555)
date added to LUP
2015-07-21 16:20:39
date last changed
2017-01-01 06:34:57
@article{cde1e65b-02c1-4e09-912e-77618b6ddc97,
  abstract     = {The filamentous fungus Hypocreajecorina (anamorph of Trichodermareesei) is the predominant source of enzymes for industrial saccharification of lignocellulose biomass. The major enzyme, cellobiohydrolase Cel7A, constitutes nearly half of the total protein in the secretome. The performance of such enzymes is susceptible to inhibition by compounds liberated by physico-chemical pre-treatment if the biomass is kept unwashed. Xylan and xylo-oligosaccharides (XOS) have been proposed to play a key role in inhibition of cellobiohydrolases of glycoside hydrolase family7. To elucidate the mechanism behind this inhibition at a molecular level, we used X-ray crystallography to determine structures of H.jecorina Cel7A in complex with XOS. Structures with xylotriose, xylotetraose and xylopentaose revealed a predominant binding mode at the entrance of the substrate-binding tunnel of the enzyme, in which each xylose residue is shifted similar to 2.4 angstrom towards the catalytic center compared with binding of cello-oligosaccharides. Furthermore, partial occupancy of two consecutive xylose residues at subsites -2 and -1 suggests an alternative binding mode for XOS in the vicinity of the catalytic center. Interestingly, the -1 xylosyl unit exhibits an open aldehyde conformation in one of the structures and a ring-closed pyranoside in another complex. Complementary inhibition studies with p-nitrophenyl lactoside as substrate indicate mixed inhibition rather than pure competitive inhibition. DatabaseThe atomic coordinates and structure factors are available in the Protein Data Bank under accession number (H. jecorina Cel7A E212Q variant, complex with xylotriose), (H. jecorina Cel7A E217Q variant, complex with xylotriose), (H. jecorina Cel7A E212Q variant, complex with xylopentaose), (H. jecorina Cel7A E217Q variant, complex with xylopentaose), (wild-type H. jecorina Cel7A, complex with xylopentaose) and (H. jecorina Cel7A E217Q variant, complex with xylotetraose).},
  author       = {Momeni, Majid Haddad and Ubhayasekera, Wimal and Sandgren, Mats and Stahlberg, Jerry and Hansson, Henrik},
  issn         = {1742-464X},
  keyword      = {biomass degradation,cellobiose,cellulase,inhibition,xylooligosaccharide},
  language     = {eng},
  number       = {11},
  pages        = {2167--2177},
  publisher    = {Federation of European Neuroscience Societies and Blackwell Publishing Ltd},
  series       = {The FEBS Journal},
  title        = {Structural insights into the inhibition of cellobiohydrolase Cel7A by xylo-oligosaccharides},
  url          = {http://dx.doi.org/10.1111/febs.13265},
  volume       = {282},
  year         = {2015},
}