Single molecule analysis reveals monomeric XPA bends DNA and undergoes episodic linear diffusion during damage search

摘要: Nucleotide excision repair (NER) removes a wide range of DNA lesions, including UV-induced photoproducts and bulky base adducts. XPA is an essential protein in eukaryotic NER, although reports about its stoichiometry role damage recognition are controversial. Here, by PeakForce Tapping atomic force microscopy, we show that human binds bends ∼60° as monomer. Furthermore, observe specificity for the helix-distorting adduct N-(2'-deoxyguanosin-8-yl)-2-acetylaminofluorene over non-damaged dsDNA. Moreover, single molecule fluorescence microscopy reveals DNA-bound exhibits multiple modes linear diffusion between paused phases. The presence increases frequency pausing. Truncated XPA, lacking intrinsically disordered N- C-termini, loses lesions shows less pausing on damaged DNA. Our data consistent with working model which monomeric DNA, displays episodic phases along pauses response to damage.