Atomic force microscopy of the EcoKI Type I DNA restriction enzyme bound to DNA shows enzyme dimerization and DNA looping.

ABSTRACT: Atomic force microscopy (AFM) allows the study of single protein-DNA interactions such as those observed with the Type I Restriction-Modification systems. The mechanisms employed by these systems are complicated and understanding them has proved problematic. It has been known for years that these enzymes translocate DNA during the restriction reaction, but more recent AFM work suggested that the archetypal EcoKI protein went through an additional dimerization stage before the onset of translocation. The results presented here extend earlier findings confirming the dimerization. Dimerization is particularly common if the DNA molecule contains two EcoKI recognition sites. DNA loops with dimers at their apex form if the DNA is sufficiently long, and also form in the presence of ATPgammaS, a n

SUBMITTER: Neaves KJ 

PROVIDER: S-EPMC2665228 | biostudies-literature | 2009 Apr

REPOSITORIES: biostudies-literature