title: Penicillium purpurogenum produces a family 1 acetyl xylan esterase containing a carbohydrate-binding module: characterization of the protein and its gene.
abstract: At 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 1 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.
authors.affiliation: Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile.
authors.forename: Felipe
authors.initials: F
authors.lastname: Gordillo
authors.forename: Valentina
authors.initials: V
authors.lastname: Caputo
authors.forename: Alessandra
authors.initials: A
authors.lastname: Peirano
authors.forename: Renato
authors.initials: R
authors.lastname: Chavez
authors.forename: Jozef
authors.initials: J
authors.lastname: Van Beeumen
authors.forename: Isabel
authors.initials: I
authors.lastname: Vandenberghe
authors.forename: Marc
authors.initials: M
authors.lastname: Claeyssens
authors.forename: Paulina
authors.initials: P
authors.lastname: Bull
authors.forename: María Cristina
authors.initials: MC
authors.lastname: Ravanal
authors.forename: Jaime
authors.initials: J
authors.lastname: Eyzaguirre
mesh_terms: D000115:Acetylesterase / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D000595:Amino Acid Sequence; D001483:Base Sequence; D020134:Catalytic Domain; D017931:DNA Primers; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D010407:Penicillium / Q000201:enzymology*; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
chemical_list: D017931:DNA Primers; D005656:Fungal Proteins; D011994:Recombinant Proteins; D000115:Acetylesterase; C081851:acetylxylan esterase