Calvin B. Harley and Robert P. Reynolds compiled and analyzed 263 E. coli promoter sequences, focusing on the -35 and -10 hexamer regions and their spacing. They used a computer program to align the promoter elements based on statistical homology to a reference set of promoters. The analysis revealed that all bases in the -35 (TTGACA) and -10 (TATAAT) hexamers were highly conserved, with 92% of promoters having an inter-region spacing of 1711 bp. Additionally, 75% of the uniquely defined start points initiated 711 bases downstream of the -10 region. The consensus sequence derived from this analysis was consistent with previous reports but included some differences in weakly conserved bases. The study provides valuable insights into promoter structure and function, and can be useful for promoter search algorithms.Calvin B. Harley and Robert P. Reynolds compiled and analyzed 263 E. coli promoter sequences, focusing on the -35 and -10 hexamer regions and their spacing. They used a computer program to align the promoter elements based on statistical homology to a reference set of promoters. The analysis revealed that all bases in the -35 (TTGACA) and -10 (TATAAT) hexamers were highly conserved, with 92% of promoters having an inter-region spacing of 1711 bp. Additionally, 75% of the uniquely defined start points initiated 711 bases downstream of the -10 region. The consensus sequence derived from this analysis was consistent with previous reports but included some differences in weakly conserved bases. The study provides valuable insights into promoter structure and function, and can be useful for promoter search algorithms.