Complete nucleotide sequence of minicircle kinetoplast DNA from Trypanosoma equiperdum

Abstract

The kinetoplast DNA of Trypanosoma equiperdum is composed of about 3000 supercoiled minicircles of 1000 base pairs and about 50 supercoiled maxicircles of 23,000 base pairs topologically interlocked so as to form a compact network. Minicircles of T. equiperdum, which are homogeneous in base sequence, were purified by equilibrium CsCl centrifugation and used as starting material for DNA sequence analysis. One minicircle is composed of 1012 base pairs and has an adenine.thymine base pair content of 72.8%. The termination codons are uniformly distributed along the molecule and restrict the coding potentiality of the molecule to oligopeptides of about 20 amino acids. The molecule contains three dyad symmetries and a sequence of 12 nucleotides is repeated six times. We also noted the presence of a region of about 130 base pairs that is almost perfectly homologous with that of the minicircles from the closely related species T. brucei.