Based on tetranucleotide parameters

a statistical mechanical model was suggested to analyze the flexibility of the Escherichia coli genome.The terminus region of replication displayed a low level of flexibility.A strong correlation between G+C content and flexibility can be seen.Average flexibilities in coding regions were found to be significantly larger than those in non-coding regions.The flexible characteristics in three class sigma promoter sequences in the Escherichia coli genome were also analyzed.