Coexistence of different base periodicities in prokaryotic genomes as related to DNA curvature, supercoiling, and transcription

TL;DR

This study investigates periodic patterns in E. coli genomes, revealing the coexistence of multiple DNA periodicities and their association with gene regulation, supercoiling, and DNA structure.

Contribution

It uncovers the coexistence of different DNA periodicities in prokaryotic genomes and links these patterns to promoter regions and gene regulation mechanisms.

Findings

Multiple DNA periodicities coexist in E. coli genome.

Periodicities are concentrated in non-coding and promoter regions.

Promoters with strong periodicities are linked to supercoiling-sensitive genes.

Abstract

We analyzed the periodic patterns in E. coli promoters and compared the distributions of the corresponding patterns in promoters and in the complete genome to elucidate their function. Except the three-base periodicity, coincident with that in the coding regions and growing stronger in the region downstream from the transcriptions start (TS), all other salient periodicities are peaked upstream of TS. We found that helical periodicities with the lengths about B-helix pitch ~10.2-10.5 bp and A-helix pitch ~10.8-11.1 bp coexist in the genomic sequences. We mapped the distributions of stretches with A-, B-, and Z- like DNA periodicities onto E.coli genome. All three periodicities tend to concentrate within non-coding regions when their intensity becomes stronger and prevail in the promoter sequences. The comparison with available experimental data indicates that promoters with the most pronounced periodicities may be related to the supercoiling-sensitive genes.