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Long W tracts are over-represented in the Escherichia coli and Haemophilus influenzae genomes.

ABSTRACT: The occurrence of DNA tracts of the three binary base combinations: R.Y, K.M and W;S has been mapped in the complete genomes of Haemophilus influenzae and Escherichia coli. A highly significant over-representation of W tracts is observed in both bacteria. The excess of W tracts is particularly striking in the 10% intercoding regions. Subdivision of intercoding regions into divergent (promoting), convergent (terminating) and sequential subregions shows that the excess of W tracts is most concentrated in the promoter regions. A particularly high excess of W tracts is observed in the first 200 bases 5' upstream of coding start sites. The data suggest that W tracts have a role in promoter function. A function as unwinding centers, analogous to the role of R.Y tracts in eukaryotes, is proposed. R.Y and K.M tracts are only modestly over-represented in the two bacteria.

SUBMITTER: Shomer B

PROVIDER: S-EPMC148734 | biostudies-other | 1999 Nov

REPOSITORIES: biostudies-other

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Long W tracts are over-represented in the Escherichia coli and Haemophilus influenzae genomes.

Shomer B B Yagil G G

Nucleic acids research 19991101 22

The occurrence of DNA tracts of the three binary base combinations: R.Y, K.M and W;S has been mapped in the complete genomes of Haemophilus influenzae and Escherichia coli. A highly significant over-representation of W tracts is observed in both bacteria. The excess of W tracts is particularly striking in the 10% intercoding regions. Subdivision of intercoding regions into divergent (promoting), convergent (terminating) and sequential subregions shows that the excess of W tracts is most concentr ...[more]

PMID: 10536160

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