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

dc.citation.firstpage5234en_US
dc.citation.journalTitleThe Journal of Biological Chemistryen_US
dc.citation.lastpage5246en_US
dc.citation.volumeNumber291en_US
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.accessioned2017-01-27T22:23:42Z
dc.date.available2017-01-27T22:23:42Z
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>The Journal of Biological Chemistry,</i> 291, (2016) American Society for Biochemistry and Molecular Biology: 5234-5246. http://dx.doi.org/10.1074/jbc.M115.694307.
dc.identifier.doihttp://dx.doi.org/10.1074/jbc.M115.694307
dc.identifier.urihttps://hdl.handle.net/1911/93801
dc.language.isoeng
dc.publisherAmerican Society for Biochemistry and Molecular Biology
dc.rightsThis is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) license.
dc.rights.urihttps://creativecommons.org/licenses/by/3.0/us/
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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