Complete nucleotide sequence of pGS18, a 62.8-kb plasmid from Geobacillus stearothermophilus strain 18.
The complete nucleotide sequence (62.8 kb) of pGS18, the largest sequenced plasmid to date from the species Geobacillus stearothermophilus, was determined. Computational analysis of sequence data revealed 65 putative open reading frames (ORFs); 38 were carried on one strand and 27 were carried on the other. These ORFs comprised 84.1% of the pGS18 sequence. Twenty-five ORFs (38.4%) were assigned to putative functions; four ORFs (6.2%) were annotated as pseudogenes. The amino acid sequences obtained from 29 ORFs (44.6%) had the highest similarity to hypothetical proteins of the other microorganisms, and seven (10.8%) had no significant similarity to any genes present in the current open databases. Plasmid replication region, strongly resembling that of the theta-type replicon, and genes encoding three different plasmid maintenance systems were identified, and a putative discontinuous transfer region was localized. In addition, we also found several mobile genetic elements and genes, responsible for DNA repair, distributed along the whole sequence of pGS18. The alignment of pGS18 with two other large indigenous plasmids of the genus Geobacillus highlighted the presence of well-conserved segments and has provided a framework that can be exploited to formulate hypotheses concerning the molecular evolution of these three plasmids.
Stuknyte
Milda
M
Department of Plant Physiology and Microbiology, Faculty of Natural Sciences, Vilnius University, Ciurlionio 21/27, 03101 Vilnius, Lithuania. Milda.Stuknyte@gf.vu.lt
Guglielmetti
Simone
S
Mora
Diego
D
Kuisiene
Nomeda
N
Parini
Carlo
C
Citavicius
Donaldas
D
D001426:Bacterial Proteins / Q000235:genetics*; D001483:Base Sequence; D004260:DNA Repair; D004261:DNA Replication; D004269:DNA, Bacterial / Q000032:analysis*; D004270:DNA, Circular; D030541:Databases, Genetic; D019143:Evolution, Molecular; D001411:Geobacillus stearothermophilus / Q000235:genetics*; D020071:Interspersed Repetitive Sequences; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010957:Plasmids; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D020539:Sequence Analysis, Protein
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004270:DNA, Circular