Isolation and functional verification of an aspartate aminotransferase gene from Neoporphyra haitanensis

• Published in: BMC plant biology 2023-03, Vol.23 (1), p.150-150, Article 150
• Main Authors: Li, Shuang, Shao, Zhanru, Lu, Chang, Duan, Delin
• Format: Article
• Language: English
• Subjects: Acid production; Algae; Amino acids; Amino Acids - metabolism; Aspartate; Aspartate aminotransferase; Aspartate Aminotransferases - metabolism; Aspartic acid; Aspartic Acid - genetics; Aspartic Acid - metabolism; Biosynthesis; Catalytic activity; Conserved sequence; Dehydrogenases; Enzyme kinetics; Flavors; Genes; Genetic aspects; Glutamic acid; Identification and classification; Kinetic parameters; Marine algae as food; Metabolism; Neoporphyra haitanensis; Physiological aspects; Protein structure; Proteins; Rhodophyta - genetics; Seaweed - metabolism; Seaweeds; Secondary structure; Sequence analysis; Transaminase; Transaminases; Transcriptional expression
• ISSN: 1471-2229; 1471-2229
• DOI: 10.1186/s12870-023-04158-2

Neoporphyra haitanensis is a commercial laver species in China. Aspartic acid is an important flavor amino acid, and aspartate aminotransferase (AAT) is a crucial enzyme in its biosynthesis. In this study, we cloned one AAT gene (NhAAT) from the red alga N. haitanensis and investigated its sequence structure, transcriptional expression and enzymatic characteristics. The purpose of our research is to obtain a functional AAT responsible for the biosynthesis of aspartic acid from red seaweeds, which has the potential to influence the flavor of N. haitanensis. Sequence analysis showed that NhAAT contains a conserved domain of Aminotran_1_2, which belongs to the transaminase superfamily. The secondary structure of NhAAT is dominated by α-helix. The results of enzymatic characterization illustrated that the NhAAT has highest catalytic activity at 45 °C and pH 7.5 in both forward and reverse reactions. The calculated K values of NhAAT was 5.67 and 6.16 mM for L-glutamic acid and L-aspartic acid, respectively. Quantitative analysis showed that the NhAAT expression of N. haitanensis collected in late harvest (Dec) was 4.5 times that of N. haitanensis collected in early harvest (Oct), while the aspartic acid content of N. haitanensis collected in late harvest (Dec) was 1.2 times that of N. haitanensis collected in early harvest (Oct). The results of enzyme kinetics indicated that NhAAT prefers to catalyze the reaction in the direction of aspartic acid production. Moreover, the trend of NhAAT expression level was consistent with that of aspartic acid content in N. haitanensis in different harvest periods. Our research is helpful to understand the accumulation and regulation of amino acids in N. haitanensis in different habitats and the taste difference of N. haitanensis in different harvest periods.