title: Phylogenetic and kinetic characterization of a suite of dehydrogenases from a newly isolated bacterium, strain SG61-1L, that catalyze the turnover of guaiacylglycerol-β-guaiacyl ether stereoisomers.
abstract: Lignin is a complex aromatic polymer found in plant cell walls that makes up 15 to 40% of plant biomass. The degradation of lignin substructures by bacteria is of emerging interest because it could provide renewable alternative feedstocks and intermediates for chemical manufacturing industries. We have isolated a bacterium, strain SG61-1L, that rapidly degrades all of the stereoisomers of one lignin substructure, guaiacylglycerol-β-guaiacyl ether (GGE), which contains a key β-O-4 linkage found in most intermonomer linkages in lignin. In an effort to understand the rapid degradation of GGE by this bacterium, we heterologously expressed and kinetically characterized a suite of dehydrogenase candidates for the first known step of GGE degradation. We identified a clade of active GGE dehydrogenases and also several other dehydrogenases outside this clade that were all able to oxidize GGE. Several candidates exhibited stereoselectivity toward the GGE stereoisomers, while others had higher levels of catalytic performance than previously described GGE dehydrogenases for all four stereoisomers, indicating a variety of potential applications for these enzymes in the manufacture of lignin-derived commodities.
authors.affiliation: CSIRO Land & Water Flagship, Acton, ACT, Australia Research School of Chemistry, Acton, ACT, Australia.
authors.forename: Shannu
authors.initials: S
authors.lastname: Palamuru
authors.affiliation: CSIRO Land & Water Flagship, Acton, ACT, Australia.
authors.forename: Nikki
authors.initials: N
authors.lastname: Dellas
authors.affiliation: CSIRO Land & Water Flagship, Acton, ACT, Australia.
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Pearce
authors.affiliation: CSIRO Land & Water Flagship, Acton, ACT, Australia.
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Warden
authors.affiliation: CSIRO Land & Water Flagship, Acton, ACT, Australia.
authors.forename: John G
authors.initials: JG
authors.lastname: Oakeshott
authors.affiliation: CSIRO Land & Water Flagship, Acton, ACT, Australia gunjan.pandey@csiro.au.
authors.forename: Gunjan
authors.initials: G
authors.lastname: Pandey
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002384:Catalysis; D006140:Guaifenesin / Q000031:analogs & derivatives* / Q000378:metabolism; D007700:Kinetics; D008031:Lignin / Q000378:metabolism*; D010084:Oxidation-Reduction; D010802:Phylogeny; D042301:Sphingomonadaceae / Q000235:genetics* / Q000378:metabolism; D013237:Stereoisomerism; D013401:Sugar Alcohol Dehydrogenases / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D006140:Guaifenesin; C046052:guaiacylglycerol-beta-guaiacyl ether; D008031:Lignin; D013401:Sugar Alcohol Dehydrogenases; C047181:guaiacylglycerol beta-O-4-guaiacyl ether dehydrogenase