Characterisation of chalcone isomerase gene isolated from Pueraria montana var. lobata plant

Abstract

Chalcone isomerase (CHI) is well-known as an important enzyme in the biosynthetic pathways such as flavonoid, isoflavonoid, and anthocyanin biosynthesis. The enzyme was investigated in some kinds of plants in Fabaceae but no research was conducted about the CHI gene of Pueraria montana var. lobata (P. lobata) in Vietnam. In order to provide more information and characterisation of the gene, our study isolated the CHI gene by RT-PCR and Sanger sequencing. The sequence of the CHI gene was analysed with nucleotide and deduced amino acid sequences to find the main domains. A full-length CDS of CHI gene from P. lobata is 672 bp encoded 224 amino acids. By using bioinformatic tools to compare, the isolated gene shared 99.7% homology with the same species reference (code D63577.1). Two different nucleotides in the gene were altered the amino acids in the protein, but the differences have not happened in active sites. Additionally, the conserved amino acids related to active catalysis of a hydrogen bond network also appeared in the P. lobata CHI gene. SWISS-MODEL was used to build the complete protein modeling showing that P. lobata CHI protein was the most similar with CHI of Medicago sativa - was defined structure in which all alpha-helix and beta-helix were completely homologies.