The DNA sequence and structural organization of the GC2 plasmid from the red alga Gracilaria chilensis.

The complete DNA sequence of the circular GC2 plasmid from the red alga Gracilaria chilensis was obtained. It contains 3827 bp and has a base composition of 75% A + T nucleotides. The sequence revealed that GC2 has two inverted repeats, each of 290 nucleotides, that border four long direct tandem repeats of 216 nucleotides. five short, direct, tandem repeats of 21-22 nucleotides were also found in the plasmid. The plasmid sequence has one major open reading frame that could encode a 411 amino acid polypeptide. Finally, the GC2 plasmid is transcriptionally active.