Identification and characterization of L-amino acid oxidase 2 gene in orange-spotted grouper (Epinephelus coioides)

Jiann Horng Leu, Chi Hang Tsai, Chia Hsun Yang, Hsin Yiu Chou, Hao Ching Wang

研究成果: 雜誌貢獻文章同行評審


Recently, L-amino acid oxidases (LAAOs) have been identified in several fish species as first-line defense molecules against bacterial infection. Here, we report the cloning and characterization of a fish LAAO gene, EcLAAO2, from orange-spotted grouper (Epinephelus coioides). The full-length cDNA is 3030 bp, with an ORF encoding a protein of 511 amino acids. EcLAAO2 is mainly expressed in the fin, gill, and intestine. Its expression is upregulated in several immune organs after challenge with lipopolysaccharide (LPS) and poly (I:C). The recombinant EcLAAO2 protein (rEcLAAO2), expressed and purified from a baculovirus expression system, was determined to be a glycosylated dimer. According to a hydrogen peroxide-production assay, the recombinant protein was identified as having LAAO enzyme activity with substrate preference for L-Phe and L-Trp, but not L-Lys as other known fish LAAOs. rEcLAAO2 could effectively inhibit the growth of Vibrio parahaemolyticus, Staphylococcus aureus, and Bacillus subtilis while exhibiting less effective inhibition of the growth of Escherichia coli. Finally, protein models based on sequence homology were constructed to predict the three-dimensional structure of EcLAAO2 as well as to explain the difference in substrate specificity between EcLAAO2 and other reported fish LAAOs. In conclusion, this study identifies EcLAAO2 as a novel fish LAAO with a substrate preference distinct from other known fish LAAOs and reveals that it may function against invading pathogens.
期刊Developmental and Comparative Immunology
出版狀態已發佈 - 7月 2021

ASJC Scopus subject areas

  • 免疫學
  • 發展生物學


深入研究「Identification and characterization of L-amino acid oxidase 2 gene in orange-spotted grouper (Epinephelus coioides)」主題。共同形成了獨特的指紋。