Title : Hyperthermostable acetyl xylan esterase - Drzewiecki_2010_Microb.Biotechnol_3_84
Author(s) : Drzewiecki K , Angelov A , Ballschmiter M , Tiefenbach KJ , Sterner R , Liebl W
Ref : Microb Biotechnol , 3 :84 , 2010
Abstract :

An esterase which is encoded within a Thermotoga maritima chromosomal gene cluster for xylan degradation and utilization was characterized after heterologous expression of the corresponding gene in Escherichia coli and purification of the enzyme. The enzyme, designated AxeA, shares amino acid sequence similarity and its broad substrate specificity with the acetyl xylan esterase from Bacillus pumilus, the cephalosporin C deacetylase from Bacillus subtilis, and other (putative) esterases, allowing its classification as a member of carbohydrate esterase family 7. The recombinant enzyme displayed activity with p-nitrophenyl-acetate as well as with various acetylated sugar substrates such as glucose penta-acetate, acetylated oat spelts xylan and DMSO (dimethyl sulfoxide)-extracted beechwood xylan, and with cephalosporin C. Thermotoga maritima AxeA represents the most thermostable acetyl xylan esterase known to date. In a 10 min assay at its optimum pH of 6.5 the enzyme's activity peaked at 90 degrees C. The inactivation half-life of AxeA at a protein concentration of 0.3 microg microl(-1) in the absence of substrate was about 13 h at 98 degrees C and about 67 h at 90 degrees C. Differential scanning calorimetry analysis of the thermal stability of AxeA corroborated its extreme heat resistance. A multi-phasic unfolding behaviour was found, with two apparent exothermic peaks at approximately 100-104 degrees C and 107.5 degrees C. In accordance with the crystal structure, gel filtration analysis at ambient temperature revealed that the enzyme has as a homohexameric oligomerization state, but a dimeric form was also found.

PubMedSearch : Drzewiecki_2010_Microb.Biotechnol_3_84
PubMedID: 21255309
Gene_locus related to this paper: thema-TM0077

Related information

Gene_locus thema-TM0077

Citations formats

Drzewiecki K, Angelov A, Ballschmiter M, Tiefenbach KJ, Sterner R, Liebl W (2010)
Hyperthermostable acetyl xylan esterase
Microb Biotechnol 3 :84

Drzewiecki K, Angelov A, Ballschmiter M, Tiefenbach KJ, Sterner R, Liebl W (2010)
Microb Biotechnol 3 :84