Table 2.

Overall sequence features of pFra, pMT1, and pHCM2

ParametersValue for plasmid or specific hosta
Y. pestis CO-92 pFraY. pestis KIM5 pMTIbS. enterica serovar Typhi CT18 pHCM2
Chromosomal G+C (%)47.647.652.05
Plasmid size (bp)96,210100984106515
Plasmid G+C (%)50.2350.1650.61
Proportion of plasmid with cross-species similarity (%)58.659.652.6 (pFra)
56.2 (pMT1)
G+C content of plasmid regions with cross-species similarity (%)51.951.951.9
G+C content of nonhomologous regions (%)47.847.849.1 non-pFra
48.9 non-pMT1
Number of Chi and Chi complement sites on one plasmid sequence strand192032
Expectedc Chi frequency (in same length sequence of random base order)2.963.063.36
Probabilityd(rank) of random Chi occurrence in plasmid based on dinucleotide frequency<10−38 (1)<10−44 (1)<10−116 (1)
  • a Unless otherwise specified, nucleotide sequences as listed in Materials and Methods.

  • b GenBank accession no. AF053947.

  • c Calculated from the base composition of the sequence (41).

  • d Determined using R'MES software for a word length of 8, i.e., ranking 65,536 possible different octanucleotides (23).