Characterization of S-Acyltransferase Gene Fragment from an Isolate of Tropical Marine Microalgae Chlorella vulgaris CBI

Abstract

S-Acyltransferase gene (pat) encodes a protein acyltransferase (PAT) that acts as an enzyme catalyzing an acyl chain transfer to the molecular acceptor, mono- or di-acylglycerol, in the biosynthesis of triacylglycerol (TAG). To date, pat from tropical marine microalgae has yet to be explored. Here, we identified a marine microalgae isolate (CBI) based on its physical morphology and 18S rRNA gene, then we isolated the pat fragment by reverse transcription (RT) PCR, followed by ligation into pGemT vector and cloning in E. coli TOP10. The pat fragment was characterized using several DNA analysis softwares. Our results showed that the isolate CBI obtained from Maluku waters was green-colored and spherical in shape with a cell diameter of 2-10 μm. A 1644-bp of 18S rRNA gene was obtained and showed a 99% nucleotide sequence similarity with 18S rRNA gene of Chlorella vulgaris (GenBank no. KF574391.1). The microalgae isolate was identified as Chlorella vulgaris CBI. Reverse transcription produced a 600-bp cDNA, in which the first 300-bp nucleotide was unidentified, however starting from nucleotide no. 301 to the end, it showed a 51% identity with the pat fragment of Chlorella variabilis (GenBank no. XP_005849764.1). A 77-residue peptide chain deduced was identified as the first N-terminus of PAT (domain transporter protein). This pat fragment of Chlorella vulgaris CBI was useful as a starting point to isolate and characterize the whole pat sequence.