Cloning of a novel L-amino acid oxidase from Trichoderma harzianum ETS 323 and bioactivity analysis of overexpressed L-amino acid oxidase.

Abstract

L-amino acid oxidases (L-AAOs) have been isolated from many organisms, such as snake, and are known to have antibacterial activity. To the best of the authors' knowledge, this is the first report of the cloning of cDNA encoding a novel Trichoderma harzianum ETS 323 L-amino acid oxidase (Th-L-AAO). The protein was overexpressed in Escherichia coli and purified to homogeneity. Comparisons of its deduced amino acid sequence with the sequence of other L-AAOs revealed the similarity to be between 9 and 24%. The molecular mass of the purified protein was 52 kDa, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme substrate specificity was highest for L-phenylalanine, and its optimal pH and temperature for activity were 7 and 40 °C, respectively; exogenous metal ions had no significant effect on activity. Circular dichroism spectroscopy indicated that the secondary structure of Th-L-AAO is composed of 17% α-helices, 28% β-sheets, and 55% random coils. The bacterially expressed Th-L-AAO also mediated antibacterial activity against both gram-positive and gram-negative food spoilage microorganisms. Furthermore, a three-dimensional protein structure was created to provide more information about the structural composition of Th-L-AAO, suggesting that the N-terminal sequence of Th-L-AAO may have contributed to the antibacterial activity of this protein.

DOI: 10.1021/jf201598z

10 Figures and Tables

Statistics

020040060020132014201520162017
Citations per Year

238 Citations

Semantic Scholar estimates that this publication has 238 citations based on the available data.

See our FAQ for additional information.

Cite this paper

@article{Cheng2011CloningOA, title={Cloning of a novel L-amino acid oxidase from Trichoderma harzianum ETS 323 and bioactivity analysis of overexpressed L-amino acid oxidase.}, author={Chi-Hua Cheng and Chia-Ann Yang and Shu-Ying Liu and Chaur-Tsuen Lo and Hsiou-Chen Huang and Fang-Chin Liao and Kou-Cheng Peng}, journal={Journal of agricultural and food chemistry}, year={2011}, volume={59 17}, pages={9142-9} }