Structural Basis of Stereospecificity in the Bacterial Enzymatic Cleavage of β-Aryl Ether Bonds in Lignin

dc.citation.firstpage5234
dc.citation.journalTitleJournal of Biological Chemistry
dc.citation.lastpage5246
dc.citation.volumeNumber291
dc.contributor.authorHelmich, Kate E.
dc.contributor.authorPereira, Jose Henrique
dc.contributor.authorGall, Daniel L.
dc.contributor.authorHeins, Richard A.
dc.contributor.authorMcAndrew, Ryan P.
dc.contributor.authorBingman, Craig A.
dc.contributor.authorDeng, Kai
dc.contributor.authorHolland, Keefe C.
dc.contributor.authorNoguera, Daniel R.
dc.contributor.authorSimmons, Blake A.
dc.contributor.authorSale, Kenneth L.
dc.contributor.authorRalph, John
dc.contributor.authorDonohue, Timothy J.
dc.contributor.authorAdams, Paul D.
dc.contributor.authorPhillips, George N.Jr.
dc.date.accessioned2017-05-02T21:09:55Z
dc.date.available2017-05-02T21:09:55Z
dc.date.issued2016
dc.description.abstractLignin is a combinatorial polymer comprising monoaromatic units that are linked via covalent bonds. Although lignin is a potential source of valuable aromatic chemicals, its recalcitrance to chemical or biological digestion presents major obstacles to both the production of second-generation biofuels and the generation of valuable coproducts from lignin's monoaromatic units. Degradation of lignin has been relatively well characterized in fungi, but it is less well understood in bacteria. A catabolic pathway for the enzymatic breakdown of aromatic oligomers linked via β-aryl ether bonds typically found in lignin has been reported in the bacterium Sphingobium sp. SYK-6. Here, we present x-ray crystal structures and biochemical characterization of the glutathione-dependent β-etherases, LigE and LigF, from this pathway. The crystal structures show that both enzymes belong to the canonical two-domain fold and glutathione binding site architecture of the glutathione S-transferase family. Mutagenesis of the conserved active site serine in both LigE and LigF shows that, whereas the enzymatic activity is reduced, this amino acid side chain is not absolutely essential for catalysis. The results include descriptions of cofactor binding sites, substrate binding sites, and catalytic mechanisms. Because β-aryl ether bonds account for 50-70% of all interunit linkages in lignin, understanding the mechanism of enzymatic β-aryl ether cleavage has significant potential for informing ongoing studies on the valorization of lignin.
dc.identifier.citationHelmich, Kate E., Pereira, Jose Henrique, Gall, Daniel L., et al.. "Structural Basis of Stereospecificity in the Bacterial Enzymatic Cleavage of β-Aryl Ether Bonds in Lignin." <i>Journal of Biological Chemistry,</i> 291, (2016) American Society for Biochemistry and Molecular Biology: 5234-5246. https://doi.org/10.1074/jbc.M115.694307.
dc.identifier.doihttps://doi.org/10.1074/jbc.M115.694307
dc.identifier.urihttps://hdl.handle.net/1911/94112
dc.language.isoeng
dc.publisherAmerican Society for Biochemistry and Molecular Biology
dc.rightsThis article is licensed under a Creative Commons CC-BY license
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/
dc.subject.keywordX-ray crystallography
dc.subject.keywordenzyme catalysis
dc.subject.keywordenzyme mechanism
dc.subject.keywordenzyme structure
dc.subject.keywordlignin degradation
dc.subject.keywordplant cell wall
dc.subject.keywordprotein structure
dc.subject.keywordstereoselectivity
dc.subject.keywordstructural enzymology
dc.titleStructural Basis of Stereospecificity in the Bacterial Enzymatic Cleavage of β-Aryl Ether Bonds in Lignin
dc.typeJournal article
dc.type.dcmiText
dc.type.publicationpublisher version
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