Methylene insertion reveals importance of phosphate-phosphate distance in DNase I cleavage

Abstract

DNase I is a major endonuclease in human serum that cleaves double-stranded DNA. While its activity has been characterized for sequence preference and structural requirements, the effects of chemical modifications on cleavage activity remain underexplored. Here we report that insertion of methylene groups at defined positions on DNA substrates significantly changes the DNase I cleavage in a position-dependent manner, leading to either enhancement or suppression depending on the insertion site. These findings indicated that chemical modifications can be used to modulate DNase I activity and suggested that local structure, particularly the distance between phosphate groups, had a significant impact on DNase I cleavage.