Single Qdot-labeled glycosylase molecules use a wedge amino acid to probe for lesions while scanning along DNA |
| |
Authors: | Dunn Andrew R Kad Neil M Nelson Shane R Warshaw David M Wallace Susan S |
| |
Institution: | The Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT 05405, USA. |
| |
Abstract: | Within the base excision repair (BER) pathway, the DNA N-glycosylases are responsible for locating and removing the majority of oxidative base damages. Endonuclease III (Nth), formamidopyrimidine DNA glycosylase (Fpg) and endonuclease VIII (Nei) are members of two glycosylase families: the helix–hairpin–helix (HhH) superfamily and the Fpg/Nei family. The search mechanisms employed by these two families of glycosylases were examined using a single molecule assay to image quantum dot (Qdot)-labeled glycosylases interacting with YOYO-1 stained λ-DNA molecules suspended between 5 µm silica beads. The HhH and Fpg/Nei families were found to have a similar diffusive search mechanism described as a continuum of motion, in keeping with rotational diffusion along the DNA molecule ranging from slow, sub-diffusive to faster, unrestricted diffusion. The search mechanism for an Fpg variant, F111A, lacking a phenylalanine wedge residue no longer displayed slow, sub-diffusive motion compared to wild type, suggesting that Fpg base interrogation may be accomplished by Phe111 insertion. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|