title: Beta glucosidase from Bacillus polymyxa is activated by glucose-6-phosphate.
abstract: Optimization of cellulose enzymatic hydrolysis is crucial for cost effective bioethanol production from lignocellulosic biomass. Enzymes involved in cellulose hydrolysis are often inhibited by their end-products, cellobiose and glucose. Efforts have been made to produce more efficient enzyme variants that are highly tolerant to product accumulation; however, further improvements are still necessary. Based on an alternative approach we initially investigated whether recently formed glucose could be phosphorylated into glucose-6-phosphate to circumvent glucose accumulation and avoid inhibition of beta-glucosidase from Bacillus polymyxa (BGLA). The kinetic properties and structural analysis of BGLA in the presence of glucose-6-phosphate (G6P) were investigated. Kinetic studies demonstrated that enzyme was not inhibited by G6P. In contrast, the presence of G6P activated the enzyme, prevented beta glucosidase feedback inhibition by glucose accumulation and improved protein stability. G6P binding was investigated by fluorescence quenching experiments and the respective association constant indicated high affinity binding of G6P to BGLA. Data reported here are of great impact for future design strategies for second-generation bioethanol production.
authors.affiliation: Biochemistry Laboratory, Department of Food and Animal Production, Center of Agroveterinary Sciences, State University of Santa Catarina, Lages, Santa Catarina 88520-000, Brazil.
authors.forename: Paulo H E
authors.initials: PH
authors.lastname: Weiss
authors.affiliation: Biophysics Laboratory, Department of Cellular Biology, University of Brasília, Brasília 70910-900, Brazil.
authors.forename: Alice C M
authors.initials: AC
authors.lastname: Álvares
authors.affiliation: Water Treatment Laboratory, Department of Environmental Engineering, Center of Agroveterinary Sciences, State University of Santa Catarina, Lages, Santa Catarina 88520-000, Brazil.
authors.forename: Anderson A
authors.initials: AA
authors.lastname: Gomes
authors.affiliation: Biochemistry Laboratory, Department of Food and Animal Production, Center of Agroveterinary Sciences, State University of Santa Catarina, Lages, Santa Catarina 88520-000, Brazil.
authors.forename: Luiz C
authors.initials: LC
authors.lastname: Miletti
authors.affiliation: Water Treatment Laboratory, Department of Environmental Engineering, Center of Agroveterinary Sciences, State University of Santa Catarina, Lages, Santa Catarina 88520-000, Brazil.
authors.forename: Everton
authors.initials: E
authors.lastname: Skoronski
authors.affiliation: Biochemistry Laboratory, Department of Food and Animal Production, Center of Agroveterinary Sciences, State University of Santa Catarina, Lages, Santa Catarina 88520-000, Brazil.
authors.forename: Gustavo F
authors.initials: GF
authors.lastname: da Silva
authors.affiliation: Biophysics Laboratory, Department of Cellular Biology, University of Brasília, Brasília 70910-900, Brazil.
authors.forename: Sonia M
authors.initials: SM
authors.lastname: de Freitas
authors.affiliation: Biochemistry Laboratory, Department of Food and Animal Production, Center of Agroveterinary Sciences, State University of Santa Catarina, Lages, Santa Catarina 88520-000, Brazil. Electronic address: maria.magalhaes@udesc.br.
authors.forename: Maria L B
authors.initials: ML
authors.lastname: Magalhães
mesh_terms: D001407:Bacillus / Q000737:chemistry* / Q000201:enzymology; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D004789:Enzyme Activation; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D005947:Glucose / Q000737:chemistry; D019298:Glucose-6-Phosphate / Q000737:chemistry*; D007700:Kinetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D013816:Thermodynamics; D001617:beta-Glucosidase / Q000737:chemistry* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D019298:Glucose-6-Phosphate; D001617:beta-Glucosidase; D005947:Glucose
keywords: BGLA; Bioethanol; Enzyme activation; Enzyme kinetics; Fluorescence spectroscopy