Molecular cloning and sequencing of Trypanosoma brucei rhodesiense putative oligosaccharyl transferase.

摘要

Genomic clone of putative Trypanosoma brucei rhodesiense oligosaccharyl transferase (TbrOST I) with ~2000 bp DNA size was obtained by PCR amplification. The size of the amplicon is akin to other kinetoplastid homologues. Sequencing revealed a partial nucleotide sequence of 2048 bp encoding a predicted protein sequence of 682 amino acid residues. TbrOST I has very high nucleotide (Ns) and amino acid (As) sequence identity to putative oligosaccharyl transferase subunit in the genomes of Trypanosoma brucei gambiense (Ns:98%; As:99%) and T. brucei (Ns:94-98%;As:93-99%). However, moderately high nucleotide identity and low amino acid sequence similarity to putative oligosaccharyl transferase subunit was observed in the genomes of Trypanosoma cruzi (Ns:74%; As:61%), Leishmania infantum (Ns:70-80%; As:46-54%), L. braziliensis (Ns:68-78%; As:46-55%) and L. major (Ns:69-76%; As:45-54%). Consequently, TbrOST I also exhibited fairly high sequence identity (71-77%) to the genome from other origins. Based on the size of amplicon and high percent identity to reported or putative oligosaccharyl transferase subunit in the genome of related species and a variety of organisms, the results strongly indicate that TbrOST I is a potential trypanosome oligosaccharyl transferase gene. The sequence data of TbrOSTI has been deposited in the GenBank with accession number GU475125.