Molecular cloning, sequence analysis and structure prediction of the related to b^0,+ amino acid transporter (rBAT) in <i>Cyprinus carpio</i> L.

Abstract

In this study, the full-length cDNA of basic amino acid transporter gene rBAT was cloned from intestinal cells of Cyprinus carpio L. using reverse transcription polymerase chain reaction (RT-PCR) and rapid-amplification of cDNA ends (RACE) methods. The amplified product was 2370 bp, including a 42 bp 5'-untranslated region, a 288 bp 3'-untranslated region, and a 2040 bp open reading frame (ORF), which encoded 679 amino acids. The predicted amino acid sequence showed high similarity with that of zebrafish (83.5%), and low similarity with that of rat (50.90%). The 3-D protein models were predicted by the comparative protein modeling program SWISS-MODEL. The prediction result displayed that the Cyprinus carpio L. rBAT had a hydrophilic cytoplasmic N terminus, a single membrane-spanning domain, and an extracellular C terminus. The structural core was a β-sheet at the N terminus. The rBAT associates with the light subunit b^0,+AT by a disulfide bridge with conserved cysteine residues (residues 109). A better understanding of the functional roles and regulation mechanism of rBAT would provide unique opportunities to investigate the biochemical processes underlying amino acid metabolism in C. carpio L., and support the foundation for improving aquaculture culture of C. carpio L.

Keywords: rBAT gene, cDNA sequence analysis, protein tertiary structure, Cyprinus carpio L