Browsing by Author "Eyzaguirre, Jaime"
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- ItemAcetyl xylan esterase II from Penicillium purpurogenum is similar to an esterase from Trichoderma reesei but lacks a cellulose binding domain(1998) Gutiérrez Ilabaca, Rodrigo Antonio; Eyzaguirre, Jaime
- ItemLa actitud religiosa de don Bernardo O'Higgins.(1961) Eyzaguirre, Jaime
- ItemAislamiento de Bacterias Termofilicas Productoras de Xilanasas(1996) Steiner, J.; Eyzaguirre, Jaime
- ItemAn eleven amino acid residue deletion expands the substrate specificity of acetyl xylan esterase II (AXE II) from Penicillium purpurogenum(2008) Colombres, Marcela; Garate, Jose A.; Lagos, Carlos F.; Araya-Secchi, Raul; Norambuena, Patricia; Quiroz, Soledad; Larrondo, Luis; Perez-Acle, Tomas; Eyzaguirre, JaimeThe soft-rot fungus Penicillium purpurogenum secretes to the culture medium a variety of enzymes related to xylan biodegradation, among them three acetyl xylan esterases (AXE I, II and III). AXE II has 207 amino acids; it belongs to family 5 of the carbohydrate esterases and its structure has been determined by X-ray crystallography at 0.9 angstrom resolution (PDB 1G66). The enzyme possesses the alpha/beta hydrolase fold and the catalytic triad typical of serine esterases (Ser90, His187 and Asp175). AXE II can hydrolyze esters of a large variety of alcohols, but it is restricted to short chain fatty acids. An analysis of its three-dimensional structure shows that a loop that covers the active site may be responsible for this strict specificity. Cutinase, an enzyme that hydrolyzes esters of long chain fatty acids and shows a structure similar to AXE II, lacks this loop. In order to generate an AXE II with this broader specificity, the preparation of a mutant lacking residues involving this loop (Gly104 to Ala114) was proposed. A set of molecular simulation experiments based on a comparative model of the mutant enzyme predicted a stable structure. Using site-directed mutagenesis, the loop's residues have been eliminated from the AXE II cDNA. The mutant protein has been expressed in Aspergillus nidulans A722 and Pichia pastoris, and it is active towards a range of fatty acid esters of up to at least 14 carbons. The availability of an esterase with broader specificity may have biotechnological applications for the synthesis of sugar esters.
- ItemAn Overview on Chemical Modification of Enzymes. the Use of Group-Specific Reagents(1996) Eyzaguirre, Jaime
- ItemB-Glucosidase From Penicillium Purpurogenum:Purification and Properties(1992) Hidalgo, M.; Eyzaguirre, Jaime
- ItemCharacterization of an α-L-arabinofuranosidase gene (abf1) from Penicillium purpurogenum and its expression(2003) Carvallo, Marcela.; Bull Simpfendorfer, Paulina; Eyzaguirre, Jaime
- ItemCharacterization of crystals of Penicillium purpurogenum acetyl xylan esterase from high-resolution X-ray diffraction(1996) Pangborn, Walter; Erman, Mary; Li, Naiyin; Burkhart, Brian M.; Pletnev, Vladimir Z.; Duax, William L.; Gutiérrez Ilabaca, Rodrigo Antonio; Peirano, Alessandra; Eyzaguirre, Jaime; Thiel, Daniel J.; Ghosh, DebashisAcetyl xylan esterase from Penicillium purpurogenum, a single-chain 23 kDa member of a newly characterized family of esterases that cleaves side chain ester linkages in xylan, has been crystallized. The crystals diffract to better than 1 Å resolution at the Cornell High Energy Synchrotron Source (CHESS) and are highly stable in the synchrotron radiation. The space group is P212121 and cell dimensions are a = 34.9 Å, b = 61.0 Å, c = 72.5 Å.
- ItemCloning, Sequencing and Expression of the cDNA of Endoxylanase B From Penilillium Purpurogenum(1997) Díaz, R.; Eyzaguirre, Jaime
- ItemConditions for Selective Degradation of Lignin by the Fungus Ganoderma Australis(1992) Eyzaguirre, Jaime
- ItemCulture conditions for enhanced cellulase production by a native strain of Penicillium purpurogenum(1994) Eyzaguirre, Jaime
- ItemDetermination of a protein structure by iodination: the structure of iodinated acetylxylan esterase(1999) Ghosh, Debashis; Gutiérrez Ilabaca, Rodrigo Antonio; Eyzaguirre, Jaime
- ItemDifferences in expression of two endoxylanase genes (xynA and xynB) from Penicillium purpurogenum(2002) Chávez, Renato.; Bull Simpfendorfer, Paulina; Eyzaguirre, Jaime
- ItemEfficient Synthesis of 4-Methyl-Umberlliferyl Dihydroferulate(2002) Leschot, Andrés.; Tapia Apati, Ricardo; Eyzaguirre, Jaime
- ItemEfficient synthesis of 4-methylumbelliferyl dihydroferulate(2002) Leschot, A.; Tapia Apati, Ricardo; Eyzaguirre, Jaime
- ItemElectrophoretic Karyotype of the Filamentous Fungus Penicillium Purpurogenum and Chromosomal Location of Several Xylanolytic Genes(2001) Chávez, R.; Eyzaguirre, Jaime
- ItemFunctional analysis of the endoxylanase B (xynB) promoter from Penicillium purpurogenum(2008) Diaz, Jheimmy; Chavez, Renato; Larrondo, Luis F.; Eyzaguirre, Jaime; Bull, PaulinaIn Penicillium purpurogenum, the gene encoding endoxylanase B (xynB) is highly expressed by xylan and repressed by glucose at the transcriptional level. The promoter of this gene has a modular structure, with eight putative XlnR binding sites in tandem (XlnR module), and upstream from them, four putative CreA binding sites (CreA module). Promoter fragments containing different modules were inserted into a plasmid, pAN49-1, which contains a basal fungal promoter linked to a reporter gene (lacZ) and its expression was studied in vivo in Aspergillus nidulans. The XlnR module is able to trigger high beta-galactosidase activity in the presence of xylan, but the lack of most XlnR sites notoriously reduces this enzymatic activity. No enzyme induction is observed if the orientation of the promoter fragment is inverted. The presence of the CreA module is necessary for glucose repression when beta-galactosidase activity is previously induced by xylan. However, when transformant strains containing the XlnR module but lacking all CreA sites were grown in glucose without pre-induction in xylan, a low beta-galactosidase activity was observed compared with the same transformants grown in xylan. These results agree with a double-lock regulatory mechanism for both direct and indirect repression of xylanolytic genes by glucose.
- ItemFunctional analysis of the endoxylanase B (xynB) promoter from Penicillium purpurogenum(2008) Díaz Muñoz, Jheimmy Maríana; Larrondo Castro, Luis Fernando; Eyzaguirre, Jaime; Bull Simpfendorfer, Paulina
- ItemPenicillium purpurogenum produces a family 1 acetyl xylan esterase containing a carbohydrate-binding module(2006) Gordillo, Felipe; Caputo, Valentina; Peirano, Alessandra; Chavez, Renato; Van Beeumen, Jozef; Vandenberghe, Isabel; Claeyssens, Marc; Bull, Paulina; Ravanal, Maria Cristina; Eyzaguirre, JaimeAt least three acetyl xylan esterases (AXE I, II and III) are secreted by Penicillium purpurogenum. This publication describes more detailed work on AXE I and its gene. AXE I binds cellulose but not xylan; it is glycosylated and inactivated by phenylmethylsulphonyl fluoride, showing that it is a serine esterase. The axe1 gene presents an open reading frame of 1278 bp, including two introns of 68 and 61 bp; it codes for a signal peptide of 31 residues and a mature protein of 351 amino acids (molecular weight 36,693). AXE I has a modular structure: a catalytic module at the amino terminus belonging to family I of the carbohydrate esterases, a linker rich in serines and threonines, and a family 1 carboxy terminal carbohydrate binding module (CBM). The CBM is similar to that of AXE from Trichoderma reesei, (with a family 5 catalytic module) indicating that the genes for catalytic modules and CBMs have evolved separately, and that they have been linked by gene fusion. The promoter sequence of axe1 contains several putative sequences for binding of gene expression regulators also found in other family 1 esterase gene promoters. It is proposed that AXE I and II act in succession in xylan degradation; first, xylan is attacked by AXE I and other xylanases possessing CBMs (which facilitate binding to lignocellulose), followed by other enzymes acting mainly on soluble substrates. (c) 2006 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.
- ItemMultiple conformations of catalytic serine and histidine in acetylxylan esterase at 0.90 angstrom(2001) Ghosh, Debashis; Eyzaguirre, Jaime