title: DNA sequence and analysis of a cryptic 4.2-kb plasmid from the filamentous cyanobacterium, Plectonema sp. strain PCC 6402.
abstract: The 4194-bp plasmid, pRF1, from Plectonema sp. Strain PCC 6402 was completely sequenced and analyzed. Seven potential open reading frames were identified. The predicted amino acid sequence of open reading frame C (ORF C) had identities of 34, 29, and 25% with Rep B from the Staphylococcus aureus plasmid, pUB110; Rep from the Bacillus amyloliquefaciens plasmid, pFTB14; and protein A from the S. aureus plasmid, pC194, respectively. A 75-amino-acid region conserved in these proteins (Rep B, Rep, and protein A) also was highly conserved in ORF C with identities of 45, 37, and 40%, respectively. Significantly, 16 of the 21 amino acids conserved in Rep B, Rep, and protein A were found at the same positions in ORF C. This ORF may encode a replication protein that includes a region conserved in some eubacteria. Additional structural features include a 425-bp region that contains palindromes, tandem repeats, and short direct repeats which may correspond to the origin of replication. An 18-bp inverted repeat was located between two open reading frames, A and G.
authors.affiliation: Department of Botany, Miami University, Oxford, Ohio 45056.
authors.forename: D R
authors.initials: DR
authors.lastname: Perkins
authors.forename: S R
authors.initials: SR
authors.lastname: Barnum
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D000458:Cyanobacteria / Q000235:genetics*; D004261:DNA Replication; D004269:DNA, Bacterial / Q000235:genetics*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010957:Plasmids; D012091:Repetitive Sequences, Nucleic Acid; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid
chemical_list: D004269:DNA, Bacterial