Penicillium purpurogenum produces a family 1 acetyl xylan esterase containing a carbohydrate-binding module: characterization of the protein and its gene.
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.
Gordillo
Felipe
F
Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Casilla 114-D, Santiago, Chile.
Caputo
Valentina
V
Peirano
Alessandra
A
Chavez
Renato
R
Van Beeumen
Jozef
J
Vandenberghe
Isabel
I
Claeyssens
Marc
M
Bull
Paulina
P
Ravanal
María Cristina
MC
Eyzaguirre
Jaime
J
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
D017931:DNA Primers; D005656:Fungal Proteins; D011994:Recombinant Proteins; D000115:Acetylesterase; C081851:acetylxylan esterase