title: Substrate-Assisted Catalysis in the Reaction Catalyzed by Salicylic Acid Binding Protein 2 (SABP2), a Potential Mechanism of Substrate Discrimination for Some Promiscuous Enzymes.
abstract: Although one of an enzyme's hallmarks is the high specificity for their natural substrates, substrate promiscuity has been reported more frequently. It is known that promiscuous enzymes generally show different catalytic efficiencies to different substrates, but our understanding of the origin of such differences is still lacking. Here we report the results of quantum mechanical/molecular mechanical simulations and an experimental study of salicylic acid binding protein 2 (SABP2). SABP2 has promiscuous esterase activity toward a series of substrates but shows a high activity toward its natural substrate, methyl salicylate (MeSA). Our results demonstrate that this enzyme may use substrate-assisted catalysis involving the hydroxyl group from MeSA to enhance the activity and achieve substrate discrimination.
authors.affiliation: Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee , Knoxville, Tennessee 37996, United States.|UT/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States.
authors.forename: Jianzhuang
authors.initials: J
authors.lastname: Yao
authors.affiliation: Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee , Knoxville, Tennessee 37996, United States.|UT/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States.
authors.forename: Haobo
authors.initials: H
authors.lastname: Guo
authors.affiliation: Department of Plant Sciences, University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: Minta
authors.initials: M
authors.lastname: Chaiprasongsuk
authors.affiliation: Department of Plant Sciences, University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: Nan
authors.initials: N
authors.lastname: Zhao
authors.affiliation: Department of Plant Sciences, University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: Feng
authors.initials: F
authors.lastname: Chen
authors.affiliation: Biosciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
authors.forename: Xiaohan
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee , Knoxville, Tennessee 37996, United States.|UT/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37830, United States.
authors.forename: Hong
authors.initials: H
authors.lastname: Guo
mesh_terms: D000215:Acylation; D002384:Catalysis; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D004950:Esterases / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism*; D012459:Salicylates / Q000378:metabolism; D013379:Substrate Specificity; D014026:Nicotiana / Q000201:enzymology
chemical_list: D010940:Plant Proteins; D012459:Salicylates; C499506:SABP2 protein, Nicotiana tabacum; D004950:Esterases; C033069:methyl salicylate