Characteristics of adjacent family 6 acetylxylan esterases fromFibrobacter succinogenesand the interaction with the Xyn10E xylanase in hydrolysis of acetylated xylan
| Autor: | Hyun-Sik Jun, G. Douglas Inglis, Dong Keun Kam, Cecil W. Forsberg, Jong K. Ha |
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| Rok vydání: | 2005 |
| Předmět: |
Molecular Sequence Data
Immunology Neocallimastix patriciarum Biology Applied Microbiology and Biotechnology Microbiology Esterase Substrate Specificity chemistry.chemical_compound Arabinoxylan Genetics Orpinomyces Amino Acid Sequence Acetylxylan esterase Molecular Biology Fibrobacter succinogenes Hydrolysis Acetylation General Medicine biology.organism_classification Xylan Xylan Endo-1 3-beta-Xylosidase chemistry Biochemistry Xylanase Acetylesterase Xylans Fibrobacter |
| Zdroj: | Canadian Journal of Microbiology. 51:821-832 |
| ISSN: | 1480-3275 0008-4166 |
| DOI: | 10.1139/w05-074 |
| Popis: | Acetylxylan esterase genes axe6A and axe6B located adjacent to one another on a Fibrobacter succinogenes chromosome have been separately cloned and their properties characterized. The corresponding esterases contained an N-terminal carbohydrate esterase family 6 catalytic domain (CD) and a C-terminal family 6 carbohydrate-binding module (CBM). The amino acid sequences of the CDs and CBMs were found to exhibit 52% and 40% amino acid similarity, respectively. The CDs of the two esterases exhibited the highest similarity to CDs of acetylxylan esterases: AxeA from the ruminal fungi Orpinomyces sp. and BnaA from Neocallimastix patriciarum. Axe6A and Axe6B were optimally active at neutral pH and had low Kmvalues of 0.084 and 0.056 mmol·L–1, respectively. Axe6A and Axe6B were shown to bind to insoluble cellulose and xylan and to soluble arabinoxylan. Axe6A deacetylated acetylated xylan at the same initial rate in the presence and absence of added Xyn10E xylanase from F. succinogenes, but the action of the xylanase on acetylated xylan was dependent upon the initial activity of Axe6A. The capacity of acetylxylan esterases to bind to plant cell wall polymers and to independently deacetylate xylan enabling xylanase to release xylooligo saccharides, documents the central role these enzymes have to improve access of F. succinogenes to cellulose.Key words: Fibrobacter succinogenes S85, acetylxylan esterase, xylanase, synergy. |
| Databáze: | OpenAIRE |
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