title: Identification of a novel carbohydrate esterase from Bjerkandera adusta: structural and function predictions through bioinformatics analysis and molecular modeling.
abstract: A new gene from Bjerkandera adusta strain UAMH 8258 encoding a carbohydrate esterase (designated as BacesI) was isolated and expressed in Pichia pastoris. The gene had an open reading frame of 1410 bp encoding a polypeptide of 470 amino acid residues, the first 18 serving as a secretion signal peptide. Homology and phylogenetic analyses showed that BaCesI belongs to carbohydrate esterases family 4. Three-dimensional modeling of the protein and normal mode analysis revealed a breathing mode of the active site that could be relevant for esterase activity. Furthermore, the overall negative electrostatic potential of this enzyme suggests that it degrades neutral substrates and will not act on negative substrates such as peptidoglycan or p-nitrophenol derivatives. The enzyme shows a specific activity of 1.118 U mg(-1) protein on 2-naphthyl acetate. No activity was detected on p-nitrophenol derivatives as proposed from the electrostatic potential data. The deacetylation activity of the recombinant BaCesI was confirmed by measuring the release of acetic acid from several substrates, including oat xylan, shrimp shell chitin, N-acetylglucosamine, and natural substrates such as sugar cane bagasse and grass. This makes the protein very interesting for the biofuels production industry from lignocellulosic materials and for the production of chitosan from chitin.
authors.affiliation: Department of Biochemistry and Molecular Biology, Facultad de Ciencias, Universidad Autónoma del Estado de Morelos. Av. Universidad 1001, Col., Chamilpa, Cuernavaca, Morelos México; Department of Environmental Biotechnology, Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos. Av. Universidad 1001, Col., Chamilpa, Cuernavaca, Morelos México.
authors.forename: Laura I
authors.initials: LI
authors.lastname: Cuervo-Soto
authors.forename: Gilberto
authors.initials: G
authors.lastname: Valdés-García
authors.forename: Ramón
authors.initials: R
authors.lastname: Batista-García
authors.forename: María
authors.initials: M
authors.lastname: del Rayo Sánchez-Carbente
authors.forename: Edgar
authors.initials: E
authors.lastname: Balcázar-López
authors.forename: Verónica
authors.initials: V
authors.lastname: Lira-Ruan
authors.forename: Nina
authors.initials: N
authors.lastname: Pastor
authors.forename: Jorge Luis
authors.initials: JL
authors.lastname: Folch-Mallol
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D019295:Computational Biology / Q000379:methods; D055453:Coriolaceae / Q000201:enzymology*; D004950:Esterases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016415:Sequence Alignment
chemical_list: D005656:Fungal Proteins; D004950:Esterases
keywords: Bjerkandera adusta; deacetylase; family 4 carbohydrate esterase; heterologous expression; lignocellulosic material degradation