Catalytic function of a newly purified exo-β-d-glucosaminidase from the entomopathogenic fungus Paecilomyces lilacinus

Chao, Cheng Fu; Chen, Yi Yun; Cheng, Chien‐Chung; Li, Yaw-Kuen

doi:10.1016/j.carbpol.2012.12.030

Cited by 10 publications

(1 citation statement)

References 26 publications

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“…Since the first CsxA was discovered in 1990 [18], several types of CsxAs have been characterized from different organisms, including bacteria [2,7,9], fungi [3,10,12,15,19,20,30], and archaea [16,28,29]. However, only seven csxA genes have been cloned and sequenced.…”

Section: Introductionmentioning

confidence: 99%

Heterologous Expression and Characterization of a Thermostable Exo-��-D-Glucosaminidase from Aspergillus oryzae

Wang

et al. 2016

Journal of Microbiology and Biotechnology

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An exo-β-D-glucosaminidase (AorCsxA) from Aspergillus oryzae FL402 was heterologously expressed and purified. The deduced amino acid sequence indicated that AorCsxA belonged to glycoside hydrolase family 2. AorCsxA digested colloid chitosan into glucosamine but not into chitosan oligosaccharides, demonstrating exo-β-D-glucosaminidase (CsxA) activity. AorCsxA exhibited optimal activity at pH 5.5 and 50°C; however, the enzyme expressed in Pichia pastoris (PpAorCsxA) showed much stronger thermostability at 50°C than that expressed in Escherichia coli (EcAorCsxA), which may be related to glycosylation. AorCsxA activity was inhibited by EDTA and most of the tested metal ions. A single amino acid mutation (F769W) in AorCsxA significantly enhanced the specific activity and hydrolysis velocity as revealed by comparison of Vmax and kcat values with those of the wild-type enzyme. The three-dimensional structure suggested the tightened pocket at the active site of F769W enabled efficient substrate binding. The AorCsxA gene was heterologously expressed in P. pastoris, and one transformant was found to produce 222 U/ml activity during the high-cell-density fermentation. This AorCsxA-overexpressing P. pastoris strain is feasible for large-scale production of AorCsxA.

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